Water reuse turns treated wastewater into a potential source for irrigation, industry, municipal services, and drinking-water supply. The available figures range from global estimates and limited reporting to observed project volumes, policy targets, and theoretical resource-recovery potential, so definitions and measurement periods matter.
Key Water Reuse Statistics
The most broadly useful water reuse figures include:
- 411 billion cubic metres of wastewater are produced worldwide each year, according to a UNEP estimate reported on its 2020 source page.
- Only 11% of total domestic and industrial wastewater is currently reused worldwide, according to UNEP’s reported 2020 estimate.
- Global wastewater production is projected to be 24% above the study’s current level by 2030, in a peer-reviewed synthesis published in 2020.
- Global wastewater production is projected to be 51% above the study’s current level by 2050, under that synthesis’s assumptions.
- 76% of wastewater received some treatment among 73 reporting countries in 2022, covering 42% of the global population; the report says this is not a complete global statistic.
- 60% of wastewater received at least secondary treatment among 42 reporting countries in 2022, covering 12% of the global population.
- 42% of household wastewater was not safely treated in the 2022 global estimate, corresponding to 113 billion cubic metres released to the environment.
- 35 of 55 countries reporting wastewater-reuse-flow data reported a measurable flow, using each country’s latest reported year from 2012–2022.
- More than 70 U.S. drinking-water-reuse projects serve over 8 million people per day, according to an EPA page accessed in 2026.
- U.S. municipal wastewater recovery for reuse was estimated at 2.2 billion gallons per day in 2019, equal to 6.6% of the 33 billion gallons per day treated.
- California reported 749,000 acre-feet of recycled-water use in 2022, under its revised volumetric reporting system.
- California’s recycled-water share of wastewater-facility outflow rose from 20% in 2019 to 25% in 2022, according to the State Water Board strategy.
- California’s 2030 water-supply strategy goal is 800,000 acre-feet per year of recycled-water use, a policy target rather than an observed result.
- Florida reused approximately 813 million gallons per day of reclaimed water in 2017, according to the state’s reuse inventory as cited by EPA.
- Five U.S. reuse-supporting WIFIA projects selected in 2023 were expected to recycle, recharge, or redirect 400 million gallons per day, a forecast of project results.
- The East Bay Municipal Utility District goal is 20 million gallons per day of reuse by 2040, for uses including irrigation, toilet flushing, and cooling.
- Full nutrient recovery from global wastewater could offset 13.4% of global agricultural demand for the studied nutrients, in a theoretical study scenario.
Contents
- Global water reuse scale and wastewater statistics
- Wastewater treatment and safe-reuse data
- U.S. water reuse volumes and project adoption
- California recycled-water trends and targets
- Potable, industrial, and municipal reuse projects
- Water reuse potential and resource recovery
Global Water Reuse Scale and Wastewater Statistics
UNEP estimates that the world produces 411 billion cubic metres of domestic and industrial wastewater per year. It also estimates that 320 billion cubic metres of pollution-filled wastewater could be purified with proper management, while only 11% of total domestic and industrial wastewater is currently reused; these figures come from UNEP’s reported 2020 source page and are estimates rather than a complete administrative census. UNEP, “Waste Pollution 101”
A peer-reviewed synthesis published in 2020 uses a different aggregated baseline: 380 billion cubic metres of global wastewater annually. The difference from UNEP’s 411-billion-cubic-metre estimate reflects differing source coverage and definitions, so the values should not be treated as a single precise global total. Global and regional potential of wastewater as a water, nutrient and energy source
| Global measure | Figure | Period or status |
|---|---|---|
| Wastewater production, UNEP | 411 billion m³/year | Reported 2020 source page |
| Wastewater production, peer-reviewed synthesis | 380 billion m³/year | Current level in study synthesis, published 2020 |
| Projected increase from study baseline | 24% | 2030 forecast |
| Projected increase from study baseline | 51% | 2050 forecast |
The same synthesis equates 380 billion cubic metres of annual wastewater with almost five times the annual flow volume of Niagara Falls. That comparison is derived from the study’s wastewater estimate and a cited average Niagara Falls flow, rather than a direct water-reuse measurement.
The study also estimates that global wastewater contains 16.6 teragrams of nitrogen, 3.0 teragrams of phosphorus, and 6.3 teragrams of potassium each year. These are theoretical embedded resource quantities, not measured recovered output or current nutrient sales.
Wastewater Treatment and Safe-Reuse Data Worldwide
The WHO/UN-Habitat 2024 report emphasizes that available wastewater data are insufficient to establish complete global statistics. In 2022, 107 countries reported some wastewater statistics, representing 73% of the world’s population, but reporting coverage varied substantially. WHO, “Progress on the proportion of domestic and industrial wastewater flows safely treated”
Among 73 countries covering 42% of the global population, 76% of total wastewater was reported as receiving some treatment. Among a smaller group of 42 countries covering 12% of the global population, 60% of total wastewater was safely treated, defined in the report as receiving at least secondary treatment.
The report’s industrial coverage was narrower still:
- Industrial wastewater treatment data came from 22 countries representing 8% of the global population.
- Among those 22 countries, 38% of industrial wastewater was reported as treated.
- Among those same countries, 27% was reported as safely treated, meaning at least secondary treatment.
For household wastewater, the 2022 estimate says 42% was not safely treated before discharge, corresponding to an estimated 113 billion cubic metres released to the environment. Of the unsafe household wastewater fraction, 45% was attributed to inadequate blackwater and greywater collection systems; that is a share of the unsafe fraction, not of all household wastewater.
Reuse-flow reporting also remains incomplete. Of 55 countries reporting some wastewater-reuse-flow data for their latest year from 2012–2022, 35 reported a measurable flow and 20 reported a zero value; the 20 zero reports represent 36.4% of reporting countries, while a reported zero may reflect no measured reuse rather than proof that no informal reuse occurs. WHO report on wastewater reuse flows
U.S. Water Reuse Volumes and Project Adoption
EPA says more than 500 facilities in the United States recycle water to meet community needs. Its page also says more than 70 U.S. drinking-water-reuse projects serve over 8 million people per day, but the project and service definitions do not provide one common national annual volume. EPA, “Basic Information about Water Reuse”
The 2019 EPA draft National Water Reuse Action Plan estimated that U.S. municipal wastewater facilities treated 33 billion gallons per day. It estimated 2.2 billion gallons per day was recovered for reuse, or 6.6% of treated municipal wastewater, while 30.6 billion gallons per day—93% of the municipal wastewater source volume in the draft’s graphic—was not recovered.
| U.S. municipal reuse measure | 2019 draft estimate |
|---|---|
| Municipal wastewater treated | 33 billion gal/day |
| Municipal wastewater recovered for reuse | 2.2 billion gal/day |
| Recovered share of treated wastewater | 6.6% |
| Recovered municipal output used for irrigation | 1.24 billion gal/day |
| Irrigation share of recovered output | 56.4% |
| Other accounted end uses | 0.66 billion gal/day, or 30% |
The same draft estimated 12 billion gallons per day of municipal wastewater was discharged directly to oceans. In another passage it stated approximately 12 billion gallons per day of municipal effluent was discharged to an ocean or estuary out of 32 billion gallons per day discharged nationwide; the draft uses 32 billion gallons per day in that passage versus 33 billion gallons per day elsewhere. EPA, “National Water Reuse Action Plan Draft”
Project examples show why capacity, output, and avoided potable supply should be distinguished. Orange County, California’s recycled-water system produces up to 100 million gallons per day for local drinking-water supply, while the Chevron Richmond refinery reuse project supplies roughly 7.5 million gallons per day and is estimated to conserve enough drinking water for more than 83,000 residents.
California Recycled-Water Trends and Targets
California’s municipal recycled-water survey recorded 714,000 acre-feet of use in 2015, 45,000 acre-feet more than in the 2009 survey. The California Department of Water Resources identifies this as a municipal recycled-water survey comparison, not a continuous annual series. California DWR, “Alternative Water Supplies”
The State Water Board strategy reports 686,000 acre-feet in 2019, 728,000 in 2020, 732,000 in 2021, and 749,000 in 2022. The strategy warns that 2019 onward used changed volumetric reporting and is not directly comparable with pre-2018 estimates.
| California measure | Reported figure | Period |
|---|---|---|
| Municipal recycled-water use | 714,000 acre-feet | 2015 |
| Recycled-water use | 686,000 acre-feet | 2019 |
| Beneficially reused recycled water | 728,000 acre-feet | 2020 |
| Recycled-water use | 732,000 acre-feet | 2021 |
| Recycled-water use | 749,000 acre-feet | 2022 |
| Share of facility outflow reused | 20% to 25% | 2019 to 2022 |
In 2020, California wastewater treatment facilities received 3.64 million acre-feet of inflow, excluding facilities treating effluent from another wastewater facility. Of that inflow, 2.4 million acre-feet were discharged and 728,000 acre-feet were beneficially recycled; permitted environmental discharge is not equivalent to unrecoverable water.
California’s Water Supply Strategy set a goal of 800,000 acre-feet per year of recycled-water use by 2030. It also set a 2040 goal of recycling an additional 1.8 million acre-feet per year, while noting that projects had not yet been identified to fully meet it. California Draft Municipal Recycled Water Resource Management Strategy
Potable, Industrial, and Municipal Reuse Projects
Reuse applications span drinking-water supply, industrial loops, irrigation, cooling, and municipal nonpotable uses. The figures below are project or state examples, not a standardized ranking.
- Florida’s 2017 Reuse Inventory Report recorded approximately 813 million gallons per day of reclaimed-water reuse.
- Florida’s reclaimed-water program was estimated to offset 442 million gallons per day of potable-quality water.
- The same Florida inventory estimated that reclaimed-water use added 252 million gallons per day back to available water supplies.
- UTC Aerospace Systems, in Connecticut, operated a closed-loop system recycling 80% of its wastewater as deionized water in the case study reported by the EPA draft.
- East Bay Municipal Utility District set a goal of 20 million gallons per day of reuse by 2040, for intended uses including irrigation, toilet flushing, and cooling. USGS, “Water use across the conterminous United States, water years 2010–20”
Five reuse-supporting WIFIA projects selected in 2023 were expected to recycle, recharge, or redirect 400 million gallons per day for beneficial uses. The named projects in Monterey, San Bernardino, Santa Cruz, Ventura, and Yucaipa Valley, California, had loan awards of $76 million, $70 million, $128 million, $63 million, and $81 million, respectively; these are loan amounts, not total project costs. EPA, “National Water Reuse Action Plan Quarterly Update”
EPA reported that its 2023 WIFIA loans closed at $3 billion for water infrastructure in 10 states, with supported communities expected to save approximately $1 billion and construction and operation expected to create nearly 20,000 jobs. Those program-wide figures cover all supported water infrastructure, not reuse-only savings or jobs.
Water Reuse Potential, Resource Recovery, and Future Targets
The global synthesis treats wastewater as a possible water, nutrient, and energy source, but its resource figures describe theoretical potential. Full nutrient recovery could offset 13.4% of global agricultural demand for the studied nutrients, while the energy embedded in global wastewater was estimated to be enough to provide electricity to 158 million households; neither figure represents current recovery performance. Peer-reviewed wastewater resource synthesis
California also has policy targets and availability estimates that should be separated from operating volumes. A 2018 recycled-water policy identified a goal of increasing statewide use from 714,000 acre-feet in 2015 to 1.5 million acre-feet by 2020, and a 2.5-million-acre-foot goal for 2030; the strategy separately reports 728,000 acre-feet in 2020 under changed measurement methods.
A 2023 study cited by California estimated that 1.8 million acre-feet per year might be available for diversion from inland surface water and coastal disposal. That potential depends on brine-discharge and instream-flow constraints as well as project construction, so it is not an observed recycled-water volume. California Draft Municipal Recycled Water Resource Management Strategy