Chapter 05

Innovations to tackle water’s critical mission areas

Key takeaways

This chapter outlines the main innovations central to the ambition of securing a future of sustainable and equitable access to water everywhere, using a mission-centred approach to radically transform how water is used, supplied, and conserved.

We must centre national and global efforts on five critical water mission areas to achieve this transformation:

Launch a new revolution in food systems to improve water productivity in agriculture while meeting the nutritional needs of a growing world population.

Conserve and restore natural habitats critical to protect green water.

Establish a circular water economy, including changes in industrial processes, so that every drop of used water generates a new drop through reuse.

Enable a clean-energy and AI-rich era with much lower water intensity.

Ensure that no child dies from unsafe water by 2030, by securing the reliable supply of potable water and sanitation for underserved communities.

These missions address the most significant and interconnected challenges of the global water crisis. The first two seek a transformation in agriculture and natural habitats, to conserve water and enhance yields, redress the neglect of green water, and stabilise the hydrological cycle. Recognising the surge of urbanisation globally, the next two missions focus on promoting circular economy solutions and reducing the water intensity of rapidly growing industries like clean energy and AI. Finally, we must ensure affordable access to clean water and sanitation for every vulnerable community.

These missions must drive policy shifts, innovation, and the alignment of the public and private sectors and communities. We must value water properly to reflect its scarcity and its critical role in sustaining the natural ecosystems that people and planet depend on. We must cease the under-pricing of water across the economy, and re-channel the subsidies that support its unsustainable usage toward promoting water-saving solutions and providing targeted support for the poor and vulnerable.

These innovations are within our reach. Many water innovations had not reached economic viability in the past, but we are now at an inflexion point. Mature and proven technologies, many less capital-intensive than before, can be scaled up more easily than even a decade ago. Others involving experimental solutions show significant promise and need support.

However, we need new ways of governing to unleash a wave of innovation and investment. Policymaking must become more collaborative, accountable, and inclusive of all voices, especially those of youth, women, marginalised communities, and the Indigenous Peoples who are on the frontlines of water conservation.

Innovation is central to the ambition of securing a future of sustainable and equitable access to water everywhere. Innovations to achieve this future are intrinsically tied to water justice. Today’s use of water in many sectors is excessive and wasteful, and skewed towards large, industrial consumers and the better-off. Solutions to manage water demand are therefore critical to ensure access for those who lack it. They must also cater to the unique needs and constraints of small-scale farmers and the informal sector and correct for insecure land and water rights.

Equally, we need proper pricing of water to discourage profligate use, and subsidies to support the poor. The widespread under-pricing of water can also skew the location of the most water-intensive crops, and water-guzzling industries, such as data centres and coal-fired power plants, to areas most at risk of water stress.

Critically, we must innovate simultaneously for water, biodiversity, and climate. Water innovation is the low-hanging fruit in efforts to tackle climate change, but there is a risk of water and climate solutions working at odds. Our missions must aim to both conserve blue and green water and reduce greenhouse gas (GHG) emissions.

This chapter outlines the key innovations needed in policies, institutions and technologies to radically transform how water is used, supplied, and conserved. They should be driven by a mission-centred approach, as set out in Chapter 4.

We must centre our ambition on tackling five critical water mission areas:

These five missions address the most significant and interconnected challenges of the global water crisis as highlighted in Chapters 2 and 3. The first two seek a transformation in agriculture and natural habitats, to conserve water and enhance yields, redress the neglect of green water, and stabilise the hydrological cycle. Recognising the surge of urbanisation globally, the next two missions focus on promoting circular economy solutions and reducing the water intensity of rapidly growing industries like clean energy and AI. Finally, we must ensure affordable access to clean water and sanitation for all.

Each of these missions require a significant scaling up of innovation and investment. They can be unlocked through the policy and governance shifts elaborated on in this chapter. Underpinning these moves, the way we do government must be different. Policymaking must become more collaborative, accountable, and inclusive of all voices, especially those of youth, women, marginalised communities, and the Indigenous Peoples who are on the frontlines of water conservation. Governments must also establish more symbiotic partnerships to tackle major water challenges, as examined in Chapter 6. It also requires a systematic effort to collect and make available data that can steer investment towards sustainable and just practices, and help communities contribute to the development of locally relevant solutions. Finally, this approach requires new forms of financing – especially patient investment with a long-term direction – which in-turn require greater certainty in policies and regulation.

Mission 1

Launch a new revolution in food systems

Agriculture is key to addressing the intertwined challenges of water, climate, and food security (Khokhar, 2017). Transforming food systems is especially necessary as food demand is projected to rise 60% between 2019 and 2050, driven by growth in the world population, urbanisation, and incomes (Falcon, Naylor, & Shankar, 2022).

Food systems are under threat from climate change; the depletion of groundwater, surface water, and green water (the moisture stored in the soil and plant life); water pollution; and inequitable distribution systems. These threats affect all regions, from Sub-Saharan Africa, where climate change is projected to impact agricultural yields (Munang, et al., 2014), to Asia, where water-intensive rice cultivation faces critically low levels of groundwater or surface water (Benavides, et al., 2023) (Tan, et al., 2014) (Wu, Wang, & Avishek, 2021); to Latin America, Africa and the EU, where droughts are causing severe losses in farm outputs (Burford, et al., 2022) (Benavides, et al., 2023); to the US Colorado River Basin, where unsustainable extraction has been outstripping future water supply (Heggie, 2020).

The Green Revolution more than a half century ago lifted agricultural yields for wheat and rice significantly, helping to avert famines and lift incomes of rural populations dramatically in some parts of the world. However, its reliance on large quantities of water, pesticides, and nitrogen-based fertilisers cannot remain viable without fundamental changes in techniques. We can no longer assume the natural stability of blue and green water flows,¹⁵ given the increasing variability in hydroclimatic conditions. Further, food systems are responsible for more than one-third of global anthropogenic greenhouse gas emissions: nitrous oxide (most of which is generated by agricultural practices) accounts for over 6% of total greenhouse gas emissions (The Business Times, 2024) (FAO, 2021). Runoff from excessive or inappropriate use of fertilisers and pesticides affects aquatic life, with nitrogen and phosphorus contributing to coastal “dead zones”, such as those appearing in the Gulf of Mexico (Howard, 2019).

We set out three goals below and how we can achieve them through a new revolution in food systems. They can transform agriculture into being both a beneficiary and custodian of natural ecosystems.

¹⁵ Blue water flows in streams and rivers, and is held in lakes, reservoirs and as groundwater in water tables and aquifers. Green water is the water stored as soil moisture and in vegetation, which returns to the air through evaporation and transpiration.

Goal 1: Improve water productivity by reducing water usage in agriculture by a third, while increasing crop yields

Agriculture accounts for 70% of freshwater withdrawals globally. Studies find that agriculture has also been responsible for about 70% of deforestation in tropical and subtropical regions (United Nations Office for Disaster Risk Reduction).

We must couple innovations for water productivity with policy measures to reduce overconsumption of water in agriculture, so as to maximise yield per drop of water, preserve soil moisture and meet growing food demands while stabilising the hydrological cycle and ensuring adequate supply of water for all.

Current irrigation systems in much of Asia rely on approaches that have existed for centuries. New irrigation technologies and other solutions can be scaled up to produce more crop per drop with the same or lower levels of water use. A major shift is required in rice cultivation, which has relied heavily on continuous flooding for irrigation. Techniques such as alternate wetting and drying, direct seeding, and rice/shrimp rotation applied in several Asian contexts (Bangladesh, Pakistan, Philippines, and southern Vietnam) have reduced water usage by 10-20% (Lampayan, Rejesus, Singleton, & Bouman, 2015) (Appendix 5.1 Box 1).

Micro-irrigation¹⁶ technologies have been found to improve water efficiency while increasing yield and crop quality. They have short payback periods of six months to two years. Soil moisture sensors and satellite technologies have also advanced and seen cost reductions, enabling farmers to optimise irrigation systems and build resilience to weather extremes (Appendix 5.1 Box 2).

There is also significant scope to expand use of fertigation for both water and fertiliser efficiency. Drip fertigation has been able to raise water use efficiency by 25%, while increasing crop yields and significantly reducing nitrogen and phosphorus concentrations in surface runoff (Li, et al., 2021) (Song, et al., 2023).

The use of rainwater harvesting systems should be enhanced to bolster the resilience of rain-fed agriculture, which accounts for 80% of the total cropland and more than half of the world’s food production (FAO, 2020). Almost 20% of global cropland is suitable for rainwater harvesting and conservation strategies, especially in large parts of East Africa and Southeast Asia. Examples of ground-up practices include zaï pits in Burkina Faso, where organic materials are placed in small soil pits in fields, enabling additional water storage of up to 500% of the soil capacity and improving soil fertility (CGIAR) (Appendix 5.1 Box 3). National governments play a critical role in ensuring that an enabling environment exists to support, promote, and regulate the role of the private sector in incremental improvements of rainfed agriculture.

Further, we should scale up examples where the use of climate-resilient seed variants, diversification of crops, and sustainable cultivation techniques (such as composting and mulching) have enabled consistent yields with resilience against weather extremities. The contexts for the successful examples in Appendix 5.1 Box 4 should be studied further to see if they can be replicated. For instance, life-science research enabled the development of resilient rice varieties that are drought- and flood-tolerant, resistant to disease, and can be cultivated with a threefold reduction of water (Luo & Yin, 2013).¹⁷

A combination of these interventions could improve irrigation efficiency and potentially yield substantial reductions in agricultural water use. While water irrigation will inevitably have to grow in the next few decades to meet growing food needs, simulations by the International Food Policy Research Institute found that three interventions taken together – increasing drip- and precision-irrigated areas, and accelerating take-up of seed variants – can generate 26% savings in irrigated water usage by 2050.¹⁸ With more aspirational targets,¹⁹ adoption of these interventions could reduce water usage by up to 50%.

However, measures to enhance water-use efficiency are unlikely to reduce agricultural water use if the savings are channelled into expanding irrigated areas, increasing cropping intensities, or a switch to more water-intensive crops. These measures for irrigation efficiency should be supported by water accounting and regulatory frameworks at field and basin levels to cap or reduce total water withdrawals.

¹⁶ Micro-irrigation consists of drip irrigation systems, subsurface drip irrigation systems, and micro-spray irrigation systems.

¹⁷ For instance, rice strain T5105, known as Temasek Rice, piloted in Banda Aceh and Yogyakarta, has a reported yield twice as high as standard with a slightly longer growth duration, without compromising grain quality (Marker-assisted breeding of Thai fragrance rice for semi-dwarf phenotype, submergence tolerance and disease resistance to rice blast, 2013). In addition, aerobic rice varieties are being developed to have drought tolerance and high yielding ability. The expected yield can be up to triple that obtained under upland conditions (Chapter Four – Aerobic Rice Systems, 2011).

¹⁸ This scenario assumes a moderate but achievable adoption level of 25%, phased in gradually from 2025 to 2050.

¹⁹ This scenario assumes a more aggressive adoption level of 50%.

Goal 2: Accelerate the shift to regenerative agriculture systems from 15% of global cropland to 50% by 2050

We must sustain soil health to improve water infiltration and storage, which are crucial to food production and the resilience of crops to droughts. Regenerative agriculture aims to achieve this through the following approaches (Appendix 5.1 Box 5):

Improving soil water retention, including cover-cropping, intercropping, mulching, and agroforestry practices.
Storing organic carbon in the soil to enhance soil water-holding capacity.
Maintaining and restoring natural and semi-natural habitats in agriculture and forestry landscapes.

These approaches are relatively low-tech and versatile solutions for most geographies and crop types. They also improve the livelihoods of smallholder farmers through lower input costs (notably water, fertilisers, pesticides), reduced labour, and increased crop yields. Farmers’ annual incomes in southern Ethiopia have increased with regenerative agriculture practices (Gebeyehu, 2023). Studies on intercropping soybean with wheat found that farmers can significantly improve profitability, with a return on investment of 15-25% over ten years (Bugas, et al., 2023).

As of 2019, only 15% of global cropland had adopted such systems (Kassam, Friedrich, & Derpsch, 2022). We must aim to adopt regenerative agriculture systems for at least 50% of global cropland by 2050, which is shown to be achievable in regions such as South America (Kassam A. , Friedrich, Derpsch, & Kienzle, 2015).²⁰ To get there, we should leverage large agroindustry coalitions to transform entire supply chains, including creating demand for regenerative agricultural products from farmers, off-takers, and traders. (Appendix 5.1 Box 6). We should also restore sustainable traditional farming techniques and take action to protect the resource rights of vulnerable groups.

²⁰ The Agribusiness Task Force (part of the Sustainable Markets Initiative) has highlighted the need to increase regenerative agriculture to make up 40% of global cropland by 2030, up from 15% today (Sustainable Markets Initiative, 2022).

Goal 3: Aim to achieve a 30% share of plant-based proteins by 2050, especially in higher-income countries with high red meat and dairy consumption

Critically, we must reduce our collective dependence on water-intensive foods. Our aim should be to gradually increase the share of plant-based proteins to about 30% of proteins in people’s diets by 2050²¹. This is especially needed in high-income countries that have high red meat and dairy consumption, but cannot be applied indiscriminately to many lower-income countries, where consumption of animal-sourced food remains important for under-nourished populations, particularly young children and pregnant women.

This global shift is ambitious, and consumer habits will take time to evolve. However, they are necessary because animal-based foods are major drivers of the agriculture sector’s impact on water use, greenhouse gas emissions, and natural habitat loss.²²

Examples show how we can make a graduated shift to plant-based and other alternative proteins²³ through research and development (R&D) and culinary innovations. Recent studies suggest that change is feasible with low-lift interventions (Sousa, 2024). For example, making plant-based dishes the main option in hospitals and on campuses, with meat only available upon request, and giving these dishes more appealing names has proven effective (Sousa, 2024).²⁴ Such subtle nudges towards plant-based food can change food habits without removing a sense of individual choice.

There is also ample scope to revitalise traditional staples that are less water-intensive, and high in protein and other nutritional content, such as varieties of millets that India is seeking to promote (India Brand Equity Foundation, 2023) (Thapak, et al.).

Plant-based and alternative proteins must be price-competitive to increase demand. Today, the cost of alternative proteins is about twice that of conventional animal proteins (Good Food Institute, 2022). Costs can be lowered by increasing the protein content of these crops, such as through breeding approaches (Good Food Institute, 2022).²⁵ The cost of microorganism-based alternatives can also be decreased by increasing the efficiency of conversion into protein and the use of lower-cost feedstocks such as fermentation byproducts (Good Food Institute, 2022).

²¹ Plant-based proteins in this report refer to foods produced from plants that can substitute directly from conventional animal-based products, such as meat, seafood, milk, eggs and dairy. The share of alternative proteins in global protein consumption, with plant-based proteins forming the much larger portion (relative to microorganism and animal-cell-based proteins) is projected to grow from 2% in 2020 to 11% by 2035. This has been estimated to rise to 16% by 2035 if there are technological step changes, and to 22% if supportive regulations and shifts in taxes and subsidies encourage a progressive shift away from conventional animal-based foods. (Witte, et al., 2021). There are encouraging signs. For example, fermentation-based proteins have achieved significant growth in funding over the last year, from public, philanthropic and commercial sources. Greater investments in experiments in the alternative protein sector will help bring it closer to achieving broad consumer appeal and commercial viability.

²² Animal-based foods are estimated to account for 57% of agricultural greenhouse gases, with beef and cow milk making up 34%. Further, about 30% of water in agriculture is directly or indirectly used for livestock production (Gerbens-Leenes, Mekonnen, & Hoekstra, 2013).

²³ There are multiple environmental benefits to consuming plant-based proteins. A gram of pulse protein utilises 90% less water on average than a gram of beef protein and 50% less than pork protein (Makonnen, et al., 2010). Plant-based protein requires less fertiliser use, leading to about 90% less aquatic nutrient pollution than conventional meat (Respect, 2023). Growing legumes, which are primary in plant-based proteins, improves soil biodiversity as well as water- and nutrient-use efficiencies in crop production (Santo, et al., 2020).

²⁴ University of California San Diego Health has been replacing some meat in hospital cafeterias with plant-based dishes such as mushroom stroganoff, resulting in a 13% reduction in red meat purchases since 2017 (Sousa, 2024).

²⁵ For example, Benson Hill, an agriculture biotechnology company, embarked on a yellow pea breeding and commercialisation programme to increase yellow pea’s protein content, improve its taste, and improve the crop for easier and more sustainable processing (2021).

Policy and institutional shifts for revolutionising food systems

The adoption of improved technologies by farmers, especially small-scale-producers, is often hampered by a range of barriers and constraints. These include financial barriers, such as affordability and limited access to loans; institutional barriers, such as insecure land tenure rights; the risks inherent in adopting new practices and technologies; and the lack of sufficient incentives to cut down on water use.

Several policy and regulatory shifts can help address these barriers. Sustainable agriculture can be strengthened in some contexts by addressing insecure land and water rights, enabling farmers to invest in measures to increase soil health and water storage. For instance, land in Africa is typically held by either the community chief or the government (MacFarquhar, 2010). In many places, farmers cannot obtain loans without providing their land titles as collateral, and hence have limited access to machinery and fertilisers (Mambondiyani, 2016).

Efforts are needed especially to empower women, who make up over 40% of the world’s agricultural labour force. They still often face significant discrimination when it comes to land and livestock ownership, participation in decision-making and access to credit and financial services (FAO, 2011).

The bulk of today’s huge agricultural subsidies have been assessed to be price-distorting and environmentally harmful.²⁶ Incentives must be provided to farmers through well-designed pricing and subsidy schemes to encourage efficient water use whilst ensuring that farmers’ livelihoods are not threatened. Inefficient and harmful subsidies should be redirected to improve water management in agriculture and support regenerative agriculture:

In Gujarat, India, a pilot programme that paid farmers for pumping less groundwater had significant impact (Hagerty, et al., 2024). In several states in India, efficient delivery of subsidies for micro-irrigation technologies has been proven effective in encouraging their adoption (Appendix 5.1 Box 7; Chapter 3).
Pajaro (California), United States (US), is a case study of how pricing irrigation water helps preserve groundwater resources and fund measures to recycle the region’s groundwater.²⁷ Indirect pricing mechanisms should also be explored.
Kilimo, an Argentinian company, incentivises farmers by providing them with a revenue stream from water savings, connecting them with corporates looking to invest in water security in the same catchment area (Global Water Intelligence, 2024).

To encourage these measures, trade negotiations that deal with domestic agricultural support could be reformed, such as by improving the transparency of subsidies to enable better assessment of the environmental externalities and encouraging their repurposing towards more equitable and environmentally sustainable outcomes.

Regenerative agriculture is likely more profitable in the long run due to crop and profit diversification and reduced agricultural input. Still, farmers could experience profit losses during the transition period (Petry, et al., 2023). Innovative support measures are needed to de-risk and support this transition, such as cross-value-chain collaboration to ensure demand for regeneratively produced crops, cost-share programmes, crop insurance schemes, and government subsidies (Majolein Brasz, 2023).

We can also scale up lessons from co-operative or cluster farming, which allows smallholders to pool their resources, employ irrigation technologies or regenerative agriculture practices at a low cost, increase their bargaining power with suppliers and buyers, and access government support and financing more easily.²⁸ Ethiopia is turning towards cluster farming as a pathway to improve water efficiency, increase yields, and reduce poverty in a sector dominated by subsistence and smallholder farmers (Dureti , Tabe-Ojong, & Owusu-Sekyere, 2023). Farm households receive proportionate benefits based on their land contributions to the cluster, and commit to cultivating crops prioritised by the cluster in adherence to farm-agronomic recommendations (Dureti , Tabe-Ojong, & Owusu-Sekyere, 2023). Similarly, Water User Associations bring together farmers, government officials, and marketers to manage a shared irrigation system, allowing farmers to play a more active role in sustainable water resource management (Chai, et al., 2014). Appendix 5.1 Box 8 offers further examples in China, Ethiopia, the Philippines, Tanzania, Uganda, and Vietnam.

Measures to enable more water-efficient technologies should be coupled with regulation and enforcement against excessive water use. Farms might otherwise expand the areas irrigated, or switch to more water-intensive, higher-value crops.²⁹ China has moved towards active groundwater management and removal of subsidies for water and water-intensive crops (Rin). We should also take a basin-wide water-management approach to mitigate the impact of reduced flows on downstream users while promoting irrigation efficiency improvements upstream (Ingrao, Strippoli, Lagioia, & Huisingh, 2023). It is important to recognise that, while individual farmers have an incentive to expand irrigated areas with the water saved, markets would correct for an excessive supply of crops in the long-term. Where there is unmet demand for crops, it also remains advantageous that they be produced on farms with the most water-efficient techniques.

Beyond irrigation, green water must be systematically assessed in economic and policy analysis. This includes recognising the economic value of green water, such as the benefits that forests and inland water ecosystems bring to rainfed agriculture through precipitation and soil moisture-retention, and how the depletion of green water contributes to droughts.

Coordinated experimentation with field-based technologies and policy interventions is needed across diverse contexts so that best practices can be made evident and scaled up. Complementing this, we must collect high-integrity water data and track water footprints across the entire supply chain to spur investments and the widespread application of water-saving innovations (Chapter 9).

Transparent regulatory frameworks and greater government involvement in the form of open research, tax credits, and subsidies are needed to unlock investments in plant-based and alternative proteins (Good Food Institute, 2022). Regulations and norms should recognise the continued role that meat-based proteins play in meeting nutritional needs, especially in lower-income countries. Clear technical thresholds should be set for alternative protein companies to gain regulatory approval; regular reviews of the evolving science are also needed. Providing pre-submission compliance advice helps companies navigate what might be complex regulatory processes and enables faster entry to market (EIT Food, 2023).

Finally, greater policy coherence and water accounting across sectors and policy domains is crucial for agricultural transformation. Concerted engagement of all stakeholders – in particular small-scale farmers and women – can bring multiple sources of knowledge, values, and information to the table, building trust and thus allowing more effective implementation of the shifts we describe (FAO, 2020) (OECD, 2018).

²⁶ This refers only to agricultural subsidies (excluding subsidies in the broader water sector). The FAO/UNDP/UNEP estimated in 2021 that USD 470 (87%) of the estimated total USD 540 billion are price-distorting and environmentally and socially harmful (UNEP, UNDP, FAO, 2021). The WTO estimated that total support for agriculture in 84 countries is USD 635 billion per year, and may be even more if including all countries, and when updated. If we apply the same 87% ratio for harmful subsidies as in the FAO UNDP/UNEP report, it will be USD 553 billion (Thibert, et al., 2019).

²⁷ Research on the programme revealed that a 20% increase in the price of groundwater resulted in a 20% decrease in the extraction of groundwater (Davenport, 2023).

²⁸ Cluster farming retains individual farm ownership and autonomy over decision-making in response to market incentives. It is distinct from collective farming, which involves a communal approach to ownership and decision making, and has had less success.

²⁹ A study in Andhra Pradesh found that subsidies for drip-irrigation systems resulted in shifts in cropping patterns to more remunerative and irrigation-reliant crops, which increased revenues. However, there was no reduction in groundwater pumping, as farmers transferred excess water to adjacent plots (Fishman, et al., 2021).

Mission 2

Conserve and restore natural habitats critical to protect green water

Since 1970, land-use change has had the largest relative negative impact on terrestrial and freshwater ecosystems. Infrastructure development, urbanisation, and agriculture account for more than 70% of deforestation pressures (EIT Food, 2023), with agricultural expansion the largest contributor (CBD Secretariat, 2020) (FAO, 2021b). These incursions into forested lands and other natural habitats have reduced green water flows and downwind precipitation, lowering agricultural yields and threatening food security, particularly in regions dependent on rainfed agriculture.

Crucially, the world must implement the goals for protecting and restoring natural ecosystems adopted in the Global Biodiversity Framework (GBF). Priority should be given to protecting and restoring areas that can generate the greatest water-security benefits. Efforts must also be made to recognise the rights of Indigenous Peoples, who are stewards of one quarter of the planet’s land, accounting for about 40% of the remaining natural lands worldwide (Fernández-Llamazares et al., 2024; Garnett et al., 2018).

Goal 1: Restore at least 30% of degraded forest and inland water ecosystems globally by 2030, aligned with GBF Target 2

Achieving the GBF target of 30% restoration of degraded forest and inland water ecosystems will restore their functional capacity, promoting the return of green water stocks and flows through precipitation and soil moisture-retention (The World Bank, 2023). According to the Intergovernmental Platform on Biodiversity and Ecosystem Services, the benefits of restoring degraded land are on average ten times higher than the costs of inaction of continuing degradation, estimated across nine different biomes (Intergovernmental Platform on Biodiversity and Ecosystem Services, 2018). The cost of restoring the damaged Waza floodplains in Cameroon was estimated to have been recovered in less than five years, and to have brought about USD 2.3 million additional income per year (Russi, et al., 2013).

Restoration of degraded ecosystems need not be expensive, as it can be achieved through simple innovations. The regreening of Uganda’s Cattle Corridor is an example. A shift to corralling cattle at night to concentrate manure catalysed a reversal in land degradation (Appendix 5.1 Box 9).

Goal 2: Conserve 30% of forest ecosystems globally by 2030, aligned with GBF Target 3

The GBF target of protecting 30% of terrestrial lands by 2030 will not bring more lands under conservation if the target is reached only in regions where forested ecosystems are intact. However, most water-scarce basins and a significant share of evaporation sheds contributing to green water transfers are in ecoregions where nature is already degraded (Chapter 3). While only 8% of the most forested ecoregions are extensively protected (50% coverage), there is potential for over an additional 40% to reach the same degree of protection (Dinerstein, et al., 2017). The 30% target should be pursued as a benchmark for nations to support the functioning of ecosystems within their jurisdiction, considering each country’s circumstances, priorities and capabilities, and respecting the rights of Indigenous Peoples and local communities, including over their traditional territories.

Goal 3: Conserve 30% of inland water ecosystems by 2030, aligned with GBF Target 3

Inland water ecosystems such as lakes, rivers, swamps, peatlands, and wetlands act as a source and purifier of water, providing resilience against flood and droughts, supporting biodiversity, and providing water for agriculture and other uses, including carbon storage and sequestration. Yet they remain under threat, with natural wetlands declining by 35% between 1970 and 2015 – three times the rate of forest loss (Convention on Wetlands, 2021). Wetlands, particularly peatlands, are critical for green water conservation and provide blue water services. They help reduce flood and drought risk with up to 90% water-holding capacity (The Ramsar Convention on Wetlands, 2021).

Policy and institutional shifts to ensure green water conservation and restoration

The importance of blue and green water in a stable hydrological cycle must be recognised as prerequisite for the restoration and conservation of natural habitats, and the overall biodiversity and climate agenda. Achieving the shared vision of living in harmony with nature hinges on a stable hydrological cycle. If blue and green water remain threatened, the aims of the Global Biodiversity Framework to protect and restore biodiversity will be undermined.

It is critical that the role of green water be recognised in decision-making processes for policies, strategies, and investment:

Nature and climate financing involving nature-based solutions should measure and account for protecting and restoring blue and green water, specifically that of forests. This includes exploring how the value of green water can be recognised and incorporated in Payment for Ecosystem Services (PES) schemes.
Regulations for water management should also encompass blue and green water. Most environmental laws and regulations focus on safeguarding the quality and quantity of blue water, neglecting the role of green water, in part due to a lack of universal metrics for green water.
Decision-makers should incorporate green water into cost-benefit evaluations, strategic environmental assessments, land use planning, and environmental-impact assessments, among other policy processes. Green water must be recognised in National Biodiversity Strategies and Action Plans (NBSAPs) of the Convention on Biological Diversity parties, to inform priorities and financing streams.

Making use of different qualitative and quantitative approaches³⁰ to reflect the multiple values will inform the implementation of policies to manage conservation and restoration (Russi, et al., 2013). For example, the Mhlathuze municipality in South Africa undertook a strategic catchment assessment to estimate in monetary terms the value its ecosystem provides, such that certain zones of and around the biodiversity hotspot were identified to be conserved while other zones were developed (Russi, et al., 2013).

Data to ensure informed decision-making is foundational for any institutional shift. We must develop a methodology to track how changes in the landscape affect blue and green water stocks and flows and vice versa and build data to determine baselines and track progress. The Global Commission on the Economics of Water advocates for the establishment of a global water data infrastructure (Chapter 9).

This mission requires particular emphasis on international partnerships:

The Congo Basin Forest Partnership seeks to protect the world’s largest carbon sink and vital source of rainfall through sustainable forest management and easing pressures on forests. Critically, the Partnership highlights the need to conserve in a way that allows for economic development (Nkuintchua , et al., 2024). Studies estimate that every USD 1 invested in restoring degraded forests can yield between USD 7 and USD 30 in economic benefits (Ding, et al., 2017).
Similarly, the Freshwater Challenge (FWC) launched at the United Nations (UN) 2023 Water Conference, a country-led initiative, aims to accelerate the restoration of 300,000 km of degraded rivers and 350 million hectares of degraded wetlands by 2030, as well as conserve intact freshwater ecosystems.

³⁰ Qualitative analysis (e.g., through participatory methods) describes the benefits and value provided by these ecosystem services that are not easily quantified (e.g., impact on security, well-being, cultural value), while quantitative data represents the state of and changes in the ecosystem services provided (e.g., groundwater availability in cubic metres, number of people who benefit from access to clean water from wetlands)

Mission 3

Establish a circular water economy

There is significant untapped potential for wastewater reuse of around 320 billion cubic metres per year (UNEP, 2023), equivalent to about 8% of total freshwater withdrawals — close to the total amount withdrawn for municipal water.³¹

There are also massive inefficiencies in water distribution. In total, some 40% of municipal urban water supply is wasted through leakage, such as from ageing pipelines³² (Jamieson, et al., 2024). Minimising these leaks will generate public savings: non-revenue water costs USD 39 billion per year globally, which could be used to improve water infrastructure. Furthermore, about 11.9 billion kg of CO₂ emissions are generated each year in treating water lost before it reaches the customer (S&P Global Ratings, 2023).

Most fundamentally, we must reimagine the linear model of water management, in which water is extracted, used, and released back into the environment. We can create a circular water economy that allows the world to capture the full value of water by retaining and reusing every drop, as well as recovering the value of all byproducts. A water recycling rate of 50% means that one drop of used water could produce another drop. But only 11% of estimated total domestic and industrial wastewater produced is reused. In addition, we should explore recovery of minerals and by-products in wastewater, which can generate revenue streams. Many components of wastewater can be recovered for beneficial purposes: water for agriculture and industry, nutrients for agriculture (nitrogen, phosphorous), and energy (methane) (US Department of Energy).

³¹ Globally, 10% of freshwater withdrawals is estimated to be used for municipal purposes.

³² On average, non-revenue water accounts for approximately 40% of the water supply, reaching as high as 80%. In Asia, non-revenue water averages 35% in cities. In Europe, it averages 26% (AVR) (Jamieson, et al., 2024).

Goal 1: Cut leakages and non-revenue water in half by 2030

A circular water economy starts with retaining water within the system and preventing loss. We must accelerate innovations to reduce non-revenue water in municipal systems by at least 50% by 2030. These include using pipes that are less leak-prone (e.g., moving from traditional cast iron to ductile iron), and employing sensor technologies for early leak detection, automated pressure control in water pipes for pumped water networks, and efficient pipe repair (Appendix 5.1 Box 10).

A satellite-based and AI-enabled leak-detection system has been validated and expanded following a successful pilot funded by the Inter-American Development Bank across Argentina, Brazil, Mexico, Trinidad & Tobago, and Uruguay. A project in Buenos Aires, covering 5,000 km of pipes, reported a 128% increase in leak detection efficiency, and water savings of 2 million m³ per year (sufficient for 16,700 persons) (2022) (ASTERRA, 2023).

Reducing non-revenue water does requires hardware and a shift in the way utilities are managed. Manila Water reduced non-revenue water in the East Zone of Metro Manila from 63% in 1997 to 13% in 2023 by strengthening community partnerships and involvement in reporting leaks and illegal connections, besides deploying technical and engineering solutions (Manila Water, 2023). To ensure sufficient attention is provided to each district, the service provision territory was restructured and decentralised with focused business plans for each district (Aqua Tech, 2023) (Appendix 5.1 Box 11).

Goal 2: Recycle 50% of water to enable every drop of used water to generate a new drop

We must drive water reuse in the municipal and industrial sectors so that, in total, every drop of used water contributes to a new drop of water.³³ While treatment for recycled water is more costly than for raw water, the prospective costs will be magnitudes smaller than the economic, health, and human toll of the day when water runs dry.

Advances in membrane and solvent-based technologies increase access to affordable water recycling (Singapore Institute of Technology , 2023). They enable efficiencies and reduce operational expenses, while increasing the yield of recovered resources (Singapore Institute of Technology , 2023). The application of specific water recycling methods (e.g., membrane-based and electro-deionisation technologies) nevertheless depends on scale and context, with industrial water in particular varying in quality requirements.

Reusing treated municipal wastewater for drinking water is becoming more common. This is usually done indirectly by adding the treated water to reservoirs or ground water³⁴ (e.g., Singapore’s NEWater or Orange County Water District’s Groundwater Replenishment System). Direct reuse, where treated wastewater is used for drinking water, is also being adopted in Namibia, the Philippines, and the US (Appendix 5.1 Box 12).

On-site water reuse is also an important alternative in urban settings. These decentralised systems reduce the risk of underutilised assets, such as in peri-urban areas of low-income countries where there is uncertainty in expected urban growth. Beyond ensuring public health, decentralised systems coupled with off-grid renewable energy sources offer the opportunity for affordable and sustainable water reuse. An added benefit is greater control over design, installation, and maintenance afforded to end-users, fostering a sense of local ownership (Appendix 5.1 Box 13).

There is substantial scope for reuse of water in industrial facilities. Wastewater from one industrial process can often be reused with minimal or no treatment in another. Optimisation at plant level allows for significant reductions in water footprints of industrial users and ensures long-term operational sustainability, particularly for water-intensive industries. Leading semiconductor wafer fabrication plants in Chinese Taipei operate at above 80% recycling rates, including through the direct reuse of reject streams from ultra-pure water production for process cooling. In food production, PepsiCo found that more than 50% of the water used during the potato-chip cooking process could be recovered and treated to safe drinking standards, saving approximately 60 million litres of water per year (PepsiCo, 2022) (Appendix 5.1 Box 14).

Reuse of wastewater (treated and non-treated) for irrigation is becoming more prevalent, particularly in arid and semi-arid countries like Australia, Egypt, and Israel. Egypt has been reusing nutrient-rich agricultural drainage water to sustain agricultural activities (IHE Delft Water and Development Partnership Programme, 2022).

³³ To illustrate, recycling 50% of the water supply once will result in every drop of used water producing 0.5 drops of usable water. This 0.5 drop of “new” usable water will then produce another 0.25 drops, then 0.125 drop and so on. Theoretically, one drop of used water will produce another drop of water (i.e., 0.5 + 0.25 +0.125 + 0.0625 +…= 1), which is a multiplier of 2. If this used water, such as greywater — wastewater (excluding toilets) generated in households or office buildings — can be recycled and used one more time onsite before being discharged to the sewer and recycled once more, the multiplier effect will be enhanced further. For example, with 50% of greywater being recycled on-site and 50% of the final used water in the sewer recycled to be reused, the multiplier will be 3.

³⁴ Indirect portable reuse introduces purified water into an environmental buffer (e.g., a groundwater aquifer or a surface water reservoir, lake, or river) before the blended water is treated at a water treatment plant and piped to the consumer.

Goal 3: Create new value by recovering other resources from wastewater treatment

Beyond reusing every drop in the water system, resources such as nutrients, energy, heavy metals, and minerals can be recovered during wastewater treatment:

Energy recovery. Wastewater volumes contain significant embedded energy³⁵ that can be used to meet electricity demand (Manzoor Qadir, 2020). Integrating used water treatment and solid waste processes can harness synergies through the water-energy-waste nexus. Singapore’s Tuas Nexus project will be powered in part by biogas produced by the co-digestion of used water sludge and food waste (National Environment Agency (Singapore)).
Nitrogen, phosphorous, and potassium recovery. Assuming full nutrient recovery from wastewater, we can meet 14.4% of global nitrogen demand as a fertiliser nutrient and 6.8% of phosphorous and 18.6% of potassium demand (Manzoor Qadir, 2020). The Durham Advanced Wastewater Treatment Facility in the US state of Oregon, which serves 500,000 customers, produces up to 40 tonnes of fertiliser every month using the nitrogen and phosphorous recovered (Ostara).
Heavy metals recovery. Effluent from mining and electroplating is typically rich in precious metals like copper and chromium. These can be recovered through technologies such as ion-exchange processes or absorbent materials (Waterman Engineers Australia).
Biosolids as fertiliser. Brazil-based Companhia de Saneamento Ambiental do Distrito Federal (CAESB) used biosolids extracted from wastewater to fertilise corn. The experiment led to higher-than-average grain yields, with biosolids 21% more efficient than mineral fertilisers (The World Bank, 2020).
Biosolids as non-conventional construction material. By transforming sludge into a safe and stable product for construction through gasification and sintering (solidifying material through heat and pressure), the problem of waste sludge disposal as a public and environmental health problem can be alleviated. Maynilad Water Services in Metro Manila, the Philippines, plans to produce bio-bricks from its water reclamation plant to be used for constructing non-load-bearing structures (Talavera, 2024).

³⁵ This energy can be recovered through: (a) thermal energy from wastewater and its treatment; and (b) chemical energy in the form of biogas generated from anaerobic digestion of wastewater sludge.

Policy and institutional shifts to promote a circular water economy

Achieving a circular water economy will require well-designed public-private partnerships (PPP) and regulations to ensure better delivery efficiency, non-revenue-water reduction, and extensive industrial wastewater recycling.

An ecosystem to support startups and growth enterprises, which are often at the forefront of these innovations, is critical to prevent them from being priced out of PPP opportunities. Governments can refine procurement policies to incentivise participation, such as by requiring local partnerships or the involvement of small and medium-sized enterprises’ participation in certain contracts. In the private sector, specialised water funds provide capital and advisory support for water and wastewater treatment startups. These can help companies participate in water plant projects, manage risks, and structure operational agreements (Water and Wastewater Asia, 2017).

Technical regulations and standards for wastewater resource recovery must be enhanced and enforced to ensure public safety, and set a common benchmark for investors to reference, and for utilities to work towards (OECD, 2020). There are few policy or regulatory frameworks that provide incentive to stakeholders to seek resource recovery from wastewater treatment. Regulations governing water utilities, public health, and environmental services must be coherent and differentiated so that they are fit for purpose. Most regulations and standards for wastewater focus on treatment and disposal into the environment, not on resource recovery and reuse (The World Bank, 2019).

Mission 4

Enable a clean-energy and AI-rich era with much lower water-intensity

As the world transitions to clean energy and harnesses the benefits of AI, the water resources crucial to this shift are often overlooked. It is paramount to address this intersection and implement strategies that advance a sustainable path towards a low-carbon and AI-enhanced future. Without compromising water availability and quality, we must radically improve water efficiency and pollution management in three areas: (1) clean-energy generation; (2) semiconductor manufacturing and data centres; and (3) mining of essential materials.

Goal 1: Generate clean energy with low water-intensity

The path to lower emissions could exacerbate or be constrained by water stress unless we reduce water use in renewable energy sources across the entire life cycle, from production to operation. The mix of new energy solutions is therefore critical, encompassing:

Low water-intensity³⁶ wind and solar photovoltaics, mainly requiring water in the upstream production of wind turbine and electrical components.
Moderate water-intensity thermal-power-based sources, including fossil fuels (oil, coal, natural gas) and renewable sources (nuclear, geothermal).
High water-intensity biofuels, which have significant surface and ground water needs for irrigation.

Figure 5.1: Water consumption by electricity generation technologies

Technologies for a water-efficient, clean-energy transition have been developed and must be scaled up. Nuclear and geothermal plants must be designed with water-efficient cooling towers and use seawater or recycled water. Biofuels should be sustainably produced based on best practices outlined in our call to revolutionise agricultural systems, above, and not involve land-use changes. (Importantly, we need to expand the production of second-generation biofuels, which turn waste biomass into resources without additional water needs and reduce carbon emissions from burning crop residues.) Solar panels require frequent water cleaning to maintain optimum performance,³⁷ an unsustainable practice in desert areas where solar farms are prevalent. A new, waterless cleaning method developed by MIT engineers leverages electrostatic repulsion to remove dust from solar panels, without the need for water (MIT News Office, 2022). Finally, green hydrogen remains an important development priority for the long term. With cumulative water consumption of 20-30 litres per kg of hydrogen, it is significantly more water-efficient than blue hydrogen, which consumes 32-39 litres per kg, considering the water consumed through natural-gas production and the eventual carbon capture and storage required (Ramirez, et al., 2023).

³⁶ Water-use intensity refers to blue water withdrawn and not returned to the source due to evaporation, transpiration, or incorporation into products, per unit of energy generated.

³⁷ Accumulation of dust on solar panels can reduce energy output by as much as 30% in just one month. Brushing the dust off the panels is not preferred given the likelihood of irreversible damage due to abrasion.

Goal 2: Improve water efficiency in industry, from cooling data centres to mining essential minerals

Solutions are imperative to ensure that rapidly growing digitalisation and the proliferation of AI do not consume an inordinate share of water (Appendix 5.1 Box 15). More water-efficient methods of producing semiconductor chips must be embraced, such as using sprays instead of baths to rinse wafers and remove impurities without sacrificing cleanliness, and reusing water used to cool down equipment. Efforts are also being made to replace wet processes with dry ones where possible (e.g., anisotropic etching with dry plasma etches instead of wet isotropic etches) (PUB, Singapore’s National Water Agency, 2022) .

Demand for data centres in the AI era will come with both increased energy needs and water use for cooling and humidification. Proper upstream design and planning are necessary to improve water efficiency and prevent harmful extraction from watersheds. Google’s data centre in Hamina, Finland, uses its proximity to the sea to utilise seawater for cooling (Metz, 2009). Data-centre provider Equinix aims to increase cooling-water efficiency by controlling the pH level and using mechanical filtration to remove solids and limit turbidity (Meta, 2016). Innovative operational solutions that reduce water use must also be considered, such as computational load shifting among Google’s data centres to optimise cooling loads (Metz, 2009) and Meta’s optimisation of relative humidity, temperature, and airflow in its data centres (Zhou, et al., 2024).

Changes are also needed in how the world mines and produces minerals such as lithium, nickel, and copper, which are foundational to both clean energy and AI – from solar panels, electric vehicles, and battery storage to electricity networks and semiconductor chips – to address their environmental consequences, as well as social impacts in each context. They currently have high water-use requirements and often pose contamination risks with long-lasting pollution effects(Gupta et al., 2024).³⁸

Moreover, up to a quarter of the world’s critical minerals are mined in arid areas or those facing high levels of water stress (Lakshman, 2024). Mining can improve its water footprint by adopting dry processing technologies and replacing evaporative cooling with less water-intensive methods. Closed-loop systems can be adopted to recycle tailings water and reuse lower-quality water from dewatering mines. To reduce pollutant discharge, mining facilities must manage runoff, and cover waste rock and ore piles. They must also employ wastewater treatment systems to remove contaminants, such as by membrane filtration and using coagulants to precipitate metals.

³⁸ For instance, nickel production is projected to grow significantly by the adoption of a hydrometallurgy process called high-pressure acid leaching to produce battery-grade nickel from limonite ores (S&P Global, 2024). This process has more than double the water intensity of conventional pyrometallurgy, which is better suited for sulphide ores (International Energy Agency, 2022). On the other hand, lithium production involves high eco-toxicity risks, mostly due to its leaching process. The shift from traditional brine-based production to rock-based lithium production also leads to an almost tenfold increase in eco-toxicity values (Songyan, et al., 2020).

Policy and institutional shifts to enable a clean-energy and AI-rich era with lower water-intensity

Robust, properly designed and implemented water policies can go a long way in ensuring water-wise energy transition and AI diffusion. They include water abstraction and pollution charges designed to signal the opportunity cost of using water and the cost of pollution.

Regulations should require large water-users to conduct water audits and develop conservation plans to identify and implement water-reuse measures, mandating minimum water recycling standards for industrial processes and adoption of water-efficient equipment.

Sectoral benchmarking is useful to identify best practices and encourage take-up by laggards. The Mining Association of Canada’s Water Stewardship Protocol and Framework is one such example (Mining Association of Canada). Their protocol comprises four performance indicators: (1) water governance, (2) operational water management, (3) watershed-scale planning, and (4) water reporting and performance indicators. It also requires facilities to engage with water users and communities-of-interest in the watershed, to participate in watershed-scale planning and governance fora, and to disclose performance against water objectives (The Mining Association of Canada).

Positive spillovers for local communities should be a priority as new industrial projects are implemented, while ensuring that local access to water resources is not restricted or degraded. As green hydrogen projects expand, policymakers should also ensure that desalination plants do not degrade surrounding marine ecosystems. Hydropower plants should be right-sited and managed within and across boundaries to minimise disruptions to downstream riparian communities.

Environmental safeguards on activities should be in place along the entire production chain – from preventing mine acid drainage, to treating pollutants associated with green hydrogen production.

Mission 5

Ensure that no child dies from unsafe water by 2030

Over 2 billion people do not have access to safely managed water. Over 1,000 children under five die every day from illnesses caused by unsafe water, and poor sanitation and hygiene (United Nations Children’s Fund (UNICEF), 2023). Water utilities have made significant progress in reaching poor and vulnerable communities in many cities (e.g., Phnom Penh in Cambodia, Porto Alegre in Brazil, and various cities in China).

We can and must bring water to every vulnerable community and child in every region. The solutions must address the more efficient and equitable distribution and use of water. They should include wider adoption of decentralised water treatment solutions that are now viable and affordable. Critically, we must ensure resilience of the water supply, including restoring and expanding wetlands and other natural storage solutions, and investing in new, energy-efficient desalination solutions.

Goal 1: Build decentralised water treatment systems

Centralised water infrastructure brings economies of scale and remains fundamental. However, it requires large capital expenditure and its extension to remote communities is often not financially viable. Technological improvements allow us to ensure access to clean and safe water for all communities by complementing centralised utilities with decentralised water treatment systems.

Water treatment technologies and processes have been developed to make this possible and can be scaled up. They include affordable yet durable membranes created by strengthening polypropylene with carbon nanoparticles. Smart approaches using sensors can be employed to provide early detection of potential membrane damage, allowing operators to monitor and adjust systems remotely (Woo, et al., 2022). With increasing demand and the challenges of implementing traditional, centralised water treatment plants, low-cost point-of-use (POU) systems offer a scalable solution in low and middle-income countries and are seeing uptake even in high-income countries. The use of membrane-based filtration, sometimes coupled with chemical treatment processes in decentralised water systems, has been shown to deliver safe water for consumptive and domestic uses in Myanmar and Tanzania. New membranes using carbon nanoparticles are also being applied in Vietnam, with the ability to treat high turbidity water without chemical pre-treatment, with vastly less sludge and at lower cost compared to conventional systems (Appendix 5.1 Box 16).

To complement decentralised water treatment systems and ensure access to safe water, passive and point-of-use chlorination of water can be adopted to provide biologically safe water. Passive chlorination can support water systems with intermittent flow, while point-of-use chlorination can disinfect water collected from informal sources. Point-of-use chlorination has potential for scalability in low-income countries, especially when paired with innovative distribution methods such as vouchers for monthly doses of dilute chlorine solution or incorporating water treatment tools into safe birthing kits (Dupas P. H., 2016) (Appendix 5.1 Box 17).

Goal 2: Close the global water storage gap, especially through rainwater harvesting and wetlands

Storage is critical to resilient and equitable water access in the face of droughts and floods.³⁹ However, water storage in wetlands has declined 40% and in groundwater up to 70% from 1971 to 2020 (McCartney, et al.). Built water storage has also declined as sediments fill man-made reservoirs, coupled with poor maintenance of structures such as dams and water tanks (Pengestu, 2023). Expanding water storage will require both natural and built systems, and can be a combination of the two, as in managed aquifer recharge (MAR).

Water harvesting is critical for mitigating droughts and dry spells and builds resilience for rainfed agriculture. About 70-80% of rainfall is typically accessible to plants as soil moisture. However, this can decrease to as little as 40-50% on inadequately managed land (Rockström), which calls for the mainstreaming of rainwater management strategies to improve yields and water productivity.

Natural storage can provide effective flood mitigation by absorbing and slowing the flow of water, while enhancing dry-season access to water through slower release, such as from mountain glaciers and snowpacks. Depending on absorptive capacity, large wetlands act as sponges, absorbing wet season flows and releasing the water over the dry season (The World Bank, 2023).

With increasing incidences of floods encroaching into residential areas, countries and municipalities are working to mitigate floods and restore natural storage. In Chad’s Doukour Valley, the Adoulous Group, a women’s co-operative, installed a water-spreading weir in a runoff bed. This weir retains water during the high-water period, functions as a dam, and recharges the groundwater table for several months, helping 17 villages in the semi-arid Sahel region irrigate their crops (The World Bank, 2024). The Netherlands’ Room for the River programme restores natural floodplains by giving rivers more room to flood safely (Dutch Water Sector, 2019). This shift from traditional, vertical flood defences to the horizontal widening of rivers increases their capacity across a wider area (Goossen, 2018).

Managed aquifer recharge is a promising adaptation that uses built structures to reverse groundwater decline.⁴⁰ Aquifers can also be artificially recharged with wastewater to exploit nature’s ability to treat wastewater. In Spain, a consortium of farmers uses seasonal excess surface water collected in basins, canals, and pits to infiltrate water to the Los Arenales aquifer. This active management of the aquifer reversed decline in groundwater levels despite lower average precipitation. If managed aquifer recharge was not implemented, farmers would have spent 16% more economic resources to pump the same water volume. Farmers were also able to sustainably maintain irrigation, with an approximately 19% increase to irrigated areas, without detriment to groundwater levels (Goossen, 2018).

³⁹ The global water storage gap is the difference between the amount of water storage needed and the amount of operational storage (natural and built) that exists for a given time and place. This gap is growing and is expected to widen further with rising water demand and greater incidence of floods and droughts.

⁴⁰ Managed aquifer recharge can be done with excess monsoonal runoff to mitigate downstream flooding and can enhance the quality and quantity of groundwater storage. Interventions ranging from field bunds and rock weirs in drainage channels, to floodwater diversion can help to reduce runoff and concentrate water to be stored in deeper aquifers.

Goal 3: Prevent water contamination at the source

Water quality around the globe is under severe threat from pollutants and contaminants, undermining ecosystem services, development, and human health. The dire situation is epitomised by eutrophication, characterised by excessive algae growth due to an overabundance of nutrients, ultimately leading to dead zones when the algae die and decompose.

While physical treatment infrastructure and regulatory standards are foundational, more innovations are required to address water contamination at its source:

Constructed wetlands filter agriculture runoff. A 12-year study in Illinois, US, found that these nature-based solutions are cost-efficient and effective at reducing nutrients in runoff that would otherwise affect local waterways. A relatively small wetland, around 6% of the agricultural area, can reduce nitrogen runoff by 50% (The Nature Conservancy, 2024).
Enforcement of industrial waste discharge can be improved with integrated environmental sensors powered by AI data analysis. Chinese Taipei’s Environmental Protection Administration has used such a system since 2019, leading to the detection of 48 incidents of illegal discharge and fines totalling over NTD 36 million (Ministry of Enviroment, 2023).
Decentralised sanitation solutions can prevent the discharge of untreated sewage. France’s SPANC (public service for off-grid sanitation) regulates the design and implementation of off-grid solutions by homeowners and monitors their proper operation and maintenance. Fees for regular inspection are billed to the owner, along with optional maintenance services provided by SPANC (Public Service France, 2022).

Goal 4: Develop and scale up energy-efficient desalination techniques

Affordable and energy-efficient desalination is part of the mix of solutions to achieve long-term water resilience. The innovations being explored include improved integration of renewable energy, better control of membrane fouling, and technologies that can work on the seabed, which reduce the impact of desalination on the marine environment and are less energy intensive.

Small-scale desalination solutions that tap renewable energy sources are growing, providing more affordable access to water in remote, arid places. While the unit-cost of production of water is more expensive than large-scale desalination plants, the savings from eliminating transmission networks means that such systems could be as cost-effective as conventional municipal-scale systems.⁴¹ Low-energy desalination solutions that do not require membranes are also being piloted by engineers at MIT and in China.⁴² The system is able to produce 4-6 litres of drinkable water per hour, and its extended lifespan and independence from electricity have enabled cheaper clean water production than that of producing tap water in the US (Chu, 2023) (Appendix 5.1 Box 18).

Improved membrane materials, such as graphene with openings the size of a single atom, aim to reduce the energy-intensity of desalination and bring affordable water filtration to countries that cannot afford large-scale desalination plants (The University of Manchester). Brine produced as part of the desalination process also provides opportunity for resource recovery, being rich in calcium and magnesium salt (Parada, et al., 2023). This provides sustainable extraction compared to land-based mining and can increase the commercial viability of desalination facilities.

Modularised subsea desalination systems are currently being trialled (Flocean). Freshwater can be produced with up to 50% reduction in desalination energy consumptions by leveraging the natural pressure of deep-sea water. Further, the lower organic content of deep-sea water (with minimal algae and bacteria due to the lack of sunlight) reduces the pre-treatment requirements as compared to a land-based facility.

⁴¹ Elemental Water Maker’s small-scale solar-powered desalination solution is fully automated and can be remotely monitored. It can achieve 70% energy savings with a further lowering of the energy input by reusing residual energy from brine (Elemental Water Makers).

⁴² This low-cost system has seawater circulating in swirling eddies, like oceanic thermohaline circulation, and is placed in a structure that absorbs the sun’s heat effectively (Ralls, 2023). This heat causes water in the circulating eddies to evaporate, leaving the salt behind. The water vapour is then condensed into pure drinking water while the residual salt is expelled.

Policy and institutional shifts to ensure access to clean water

Utilities and governments must employ an efficient and equitable demand-management model that provides users with the water supply they require, discourages overuse of water, and ensures that the poor are subsidised. A multi-pronged strategy involving utilities and regulators is necessary.

Price and subsidy policies should incentivise conservation and ensure access to water resources for the poor and vulnerable. Regularly adjusted tariffs are necessary to provide water utilities with revenue for routine operations, maintenance, and investment in new infrastructure. They also provide the resources to extend the reach of water infrastructure which, coupled with targeted support for the poor and underserved, is critical to ensuring inclusivity. Various tariff structures and subsidies can achieve this (Leflaive, et al., 2020):

In Chile, an increasing block tariff coupled with coupons for low-income households helps the poor pay their water bills (Leflaive, et al., 2020). The increasing block tariff has a base price for a certain level of water consumption with additional tariffs on higher consumption ‘blocks’. This encourages lower water usage and ensures a stream of revenue to support the utility’s operating costs and investments.
Singapore has adopted a block tariff system for households, coupled with targeted subsidies for lower- and middle-income households. The large, first tariff block includes a water conservation tax, and enables the recovery of the long-term cost of producing and distributing water. While 96% of households fall into this first block, a significant proportion of them receive a targeted and progressive rebate to ensure affordability.
A study in Kenya showed that a uniform price (such as at the marginal cost of service delivery) alongside a targeted rebate subsidy based on the amount of revenue in excess of costs yields optimal social, economic, and financial outcomes (Fuente, Kabubo-Mariara, Kimuyu, Mwaura, & Whittington, 2019).

Governments can also implement differentiated regulatory regimes to achieve last-mile water supply and sanitation service delivery. In 2017, the Colombian national government introduced differential schemes to incentivise utilities to close persistent gaps in service provision for the poor, initially setting lower regulatory standards with the expectation that these will progressively rise over time. This approach yielded positive results in Medellin, where services were extended to nearly 15,000 previously unserved households (Polaníai, 2022) (Polanía, 2021) (Appendix 5.1 Box 19).

On the demand side, measuring consumption accurately by mandating the installation of water metres encourages users to be more conscious of their consumption. The advent of smart water meters – which provide more granular and real-time insights on water use – opens a new frontier for demand management and data-driven behavioural nudging practices (e.g., goal setting, comparative data, gamification, and loss-aversion messaging).

Many contexts offer greater opportunities to tackle local water and health challenges together. By working collaboratively rather than in silos, we can unlock more impactful solutions for safe water, sanitation, hygiene, and health, such as by incorporating water treatment (including chlorine-based products) into health packages. We should strengthen such innovative partnerships at every level.

Meanwhile, national public finance coupled with central government funding must support decentralised systems. While central governments should facilitate technical assistance to local governments, direct channelling of funds to district authorities can significantly enlarge their water and sanitation capabilities. Another mechanism is earmarked grants that ensure there are sufficient funds for water and sanitation. Upon implementation, decentralised solutions can be kept affordable through collection of user fees. User fees for cost recovery allows these systems to remain financially sustainable (Appendix 5.1 Box 20). For example, Portugal has a model in which municipalities are both shareholders and clients of multi-municipal water utility companies, alongside the central government holding the majority equity stake (Oliveria, 2023). This model strikes a balance between maintaining municipal jurisdiction over water systems and aggregating multiple municipal utilities unto larger operational units to enable quicker infrastructure development, better management, improvements in technical capacity, and better absorption of EU funds (Zenha, et al., 2017).

Ultimately, management of blue and green water storage, especially wetlands, must be a multilateral priority. It requires good data on water storage, to be shared across countries who share the same precipitationshed (Chapter 9). Remote sensing plays a key role in providing geospatial information required to monitor changes in water storage. Measuring surface-water elevation using earth observation technology can provide estimates of changes in total water storage.

Solving water: An unprecedented opportunity

A future of sustainable, affordable, and equitable access to clean water everywhere is fully within reach. Water innovations have had uneven success in achieving economic viability in the past, especially without a supportive policy environment. However, we are at an inflexion point. Mature and proven technologies, many less capital-intensive than before, can be scaled up more easily than even a decade ago. Others involving experimental solutions show significant promise and need support.

The fundamental opportunity lies in reorienting policies and institutions, through active consultation with all stakeholders, to spur a wave of innovation and investment centred on the five missions set out in this chapter. Priority must be given to discouraging land-use changes that negatively impact blue and green water. Crucially, water must be priced properly, accompanied with targeted financial support to enable access by every vulnerable community, so as to discourage excessive consumption and supporting demand for water-saving innovations in every sector of the economy.

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