Wastewater treatment statistics show a large global gap between wastewater generation and safe treatment. The available measures cover household flows, industrial reporting, public treatment works, infrastructure needs, and climate exposure, but their populations and definitions differ.
Key Wastewater Treatment Statistics
The most useful headline figures span global household flows, regional access, national systems, and infrastructure:
- In 2022, 193 billion m³ of household wastewater was generated globally, according to a UN-Water estimate.
- In 2022, 155 billion m³ of global household wastewater was safely treated, according to a UN-Water estimate.
- In 2022, about 58% of global household wastewater flows were safely treated.
- In 2022, 113 billion m³ of global household wastewater was not safely treated, according to the UN-Water table estimate.
- In 2022, 36 billion m³ of industrial wastewater generation was covered by the reporting dataset, which was not a fully global total.
- In 2022, 27% of reported industrial wastewater flow was safely treated in the reporting countries.
- In 2024, 92.2% of household wastewater flow was safely treated in Australia and New Zealand.
- In 2024, 87.2% of household wastewater flow was safely treated in Europe and Northern America.
- In 2024, 19.4% of household wastewater flow was safely treated in Sub-Saharan Africa.
- In 2024, 92.0% of household wastewater flow was safely treated in high-income countries.
- In 2024, 43.5% of household wastewater flow was safely treated in lower- and middle-income countries.
- In January 2022, 17,544 publicly owned treatment works served 270.4 million people in the United States.
- In 2022, about 42% of the U.S. population was served by publicly owned treatment works with advanced treatment.
- In 2022, $630.1 billion in U.S. clean-water infrastructure needs was reported for 2022–2041.
- In 2022, $345.7 billion, or 55% of total U.S. Clean Watersheds Needs Survey needs, was wastewater infrastructure.
- In 2018, 82% of Europe’s urban wastewater was collected and treated in line with EU standards.
- In the EEA flood-exposure analysis, nearly 36% of wastewater treatment plants were located in areas prone to riverine flooding.
Contents
- Global wastewater treatment flows and safe treatment
- Regional wastewater treatment rates
- Income-group wastewater treatment data
- U.S. wastewater treatment coverage and trends
- Wastewater infrastructure needs and costs
- European urban wastewater performance and flood exposure
Global Wastewater Treatment Flows and Safe Treatment
UN-Water’s household indicator covers blackwater and greywater and defines safe treatment through collection, delivery to treatment, and adequate treatment. It is therefore stricter than simply counting wastewater that receives any treatment.
The 2022 global estimate recorded 193 billion m³ of household wastewater generated, of which 155 billion m³ was safely treated. The same table estimated 113 billion m³ was not safely treated, and placed the safely treated share at about 58% of household flow.
These are global representative estimates, and reporting coverage varies by country. UN-Water, Progress on the Proportion of Domestic and Industrial Wastewater Flows Safely Treated: 2024 Update
The comparable 2020 estimate was 271 billion m³ of household wastewater generated, with a global safely treated rate of 56%. The changing coverage and estimate basis mean the 2020 and 2022 volumes should not be read as a simple growth series.
Industrial data are narrower because they cover reporting countries rather than a complete global total:
- The 2022 reporting dataset covered 36 billion m³ of industrial wastewater generation.
- Reported industrial wastewater treated totaled 8 billion m³ in 2022, while 3 billion m³ was reported as safely treated.
- The reported proportion treated was 38% in 2022, compared with 27% safely treated.
- Reported wastewater reuse volume was 36 billion m³ in 2022; reuse is distinct from safe treatment.
These industrial figures are observed or estimated within incomplete reporting coverage and are not population-weighted global rates. The household and industrial measures should therefore be interpreted as different statistical lenses, not a single combined total.
Regional Wastewater Treatment Rates and Geographic Gaps
UN-Water’s 2024 regional estimates show substantial differences in the share of household wastewater flow safely treated:
| Region or grouping | Safely treated household flow, 2024 |
|---|---|
| Australia and New Zealand | 92.2% |
| Europe and Northern America | 87.2% |
| Eastern and South-Eastern Asia | 65.3% |
| Northern Africa and Western Asia | 64.5% |
| Latin America and the Caribbean | 36.6% |
| Central and Southern Asia | 27.9% |
| Sub-Saharan Africa | 19.4% |
| Oceania | 15.7% |
| Small Island Developing States | 39.4% |
| Least Developed Countries | 19.5% |
The table measures household wastewater flow, not treatment-plant performance or the number of people connected to a particular technology. Oceania’s estimate also carries limited reporting coverage, while country data availability differs across Small Island Developing States. UN-Water, Progress on the Safe Treatment of Domestic Wastewater: 2025 Briefing Note
The regional pattern places the highest 2024 estimates in Australia and New Zealand and Europe and Northern America, while Sub-Saharan Africa, Oceania, and the Least Developed Countries were below 20%. Those comparisons describe reported household-flow treatment rates and should not be generalized to all domestic or industrial wastewater.
Income-Group Wastewater Treatment Data and Access Differences
The 2024 income-group estimates also show a wide spread:
| Income grouping | Safely treated household flow, 2024 |
|---|---|
| High-income countries | 92.0% |
| Upper-middle-income countries | 53.9% |
| Lower- and middle-income countries | 43.5% |
| Lower-middle-income countries | 32.6% |
| Low-income countries | 26.1% |
These are World Bank groupings used in the briefing, not simple averages of countries. Reporting is uneven, particularly for low-income countries, so the figures describe the available household-flow estimates rather than a complete census of service quality. UN-Water, Progress on the Safe Treatment of Domestic Wastewater: 2025 Briefing Note
Historical comparison points show the measurement series changing over time:
- High-income countries safely treated 90.4% of household wastewater flow in 2020.
- Low-income countries safely treated 23.2% of household wastewater flow in 2022.
- Least Developed Countries safely treated 17.5% of household wastewater flow in 2022.
The 2020, 2022, and 2024 observations should retain their stated classifications and reporting limitations. They are not evidence that every country followed the same trajectory.
U.S. Wastewater Treatment Coverage and Treatment-Level Trends
The U.S. Environmental Protection Agency’s 2022 Clean Watersheds Needs Survey provides facility and population measures that are not directly comparable with UN-Water’s global household-flow indicator. In January 2022, the United States had 17,544 publicly owned treatment works serving 270.4 million people, or 82% of the U.S. population.
Treatment level changed materially across the EPA’s historical comparison:
| U.S. population served by POTWs | 1972 | 2022 |
|---|---|---|
| Advanced treatment | Less than 4% | About 42% |
| Less-than-secondary treatment | Almost 28% | About 1% |
The advanced-treatment measure means treatment more stringent than secondary treatment in the survey. The less-than-secondary measure is a treatment-level trend, not a direct estimate of the share of all wastewater safely treated under the UN-Water definition. EPA, 2022 Clean Watersheds Needs Survey Fact Sheet
Nearly 17,000 U.S. POTWs were represented in EPA’s national sewershed dataset using 2020 census coverage. That dataset count is distinct from the 17,544 CWNS facilities, and tribal wastewater needs are handled separately.
Wastewater Infrastructure Needs and Capital Cost Statistics
The 2022 U.S. Clean Watersheds Needs Survey reported $630.1 billion in total clean-water infrastructure needs from January 1, 2022, through December 31, 2041. These are reported capital needs in January 2022 dollars, not actual expenditure, and EPA warns that the total likely understates national need.
Wastewater infrastructure accounted for $345.7 billion, or 55% of the total. The category includes treatment, conveyance, combined sewer overflow correction, reuse, and desalination, so it is broader than treatment-plant construction alone. EPA, 2022 Clean Watersheds Needs Survey Fact Sheet
The detailed 2022 categories were:
- Secondary wastewater treatment needs were $66.6 billion.
- Advanced wastewater treatment needs were $83.6 billion.
- Conveyance repair and new conveyance needs totaled $151.1 billion.
- Combined sewer overflow correction needs were $36.5 billion.
- Water-reuse needs were $7.7 billion, reported by 31 states.
EPA’s survey-category comparison from 2012 to 2022 found that advanced-treatment needs increased 36%, or $22.1 billion, while conveyance repair and new-conveyance needs increased 27%, or $32.4 billion. Combined sewer overflow correction needs decreased 39%, or $23.0 billion; these are category comparisons, not inflation-free spending growth. EPA, 2022 Clean Watersheds Needs Survey Report to Congress
Small communities contributed more than 60% of all wastewater submissions, totaling 14,457 submissions. Those submissions covered 32.8 million people, or 12% of the U.S. population, and $47.1 billion in wastewater needs; the analysis generally defines a small community as having 10,000 or fewer people and does not represent all decentralized systems.
European Urban Wastewater Performance and Flood Exposure
In 2018, 82% of Europe’s urban wastewater was collected and treated in line with EU standards. The European Environment Agency notes that this Urban Waste Water Treatment Directive figure differs from Eurostat-connected indicators because the reporting requirements differ. EEA, Population connected to at least secondary wastewater treatment
For the EEA indicator, secondary treatment means at least 70% biochemical oxygen demand removal and 75% chemical oxygen demand removal. Those thresholds define a treatment level; they are not a measured average result for every plant.
Wastewater infrastructure also faces geographic climate exposure. Nearly 36% of wastewater treatment plants in the EEA flood-exposure analysis were located in areas prone to riverine flooding, compared with nearly 15% of industrial facilities in Europe.
These are modeled potential-exposure estimates based on facility locations and flood-prone areas, not observations that plants flooded, failed, or were damaged. EEA Climate-ADAPT, Industrial and wastewater facility exposure to floods