Drinking water safety is measured in several different ways: access to safely managed services, regulatory compliance, contaminant concentrations, reported outbreaks and modeled health outcomes. The figures below keep those definitions separate while covering global 2022 estimates and U.S. evidence from 2014, 2015–2020 and 2023.
Key Drinking Water Safety Statistics
The most broadly useful figures include:
- In 2022, 73% of the global population used safely managed drinking water services.
- In 2022, 2.2 billion people globally lacked safely managed drinking water.
- In 2022, 62% of rural people globally used safely managed drinking water services.
- In 2022, 81% of urban people globally used safely managed drinking water services.
- In 2022, 115 million people globally collected untreated water directly from surface sources.
- In calendar year 2023, 148,541 active public water systems operated in the United States.
- In 2023, 72% of U.S. public water systems had no reported drinking-water-standard violations.
- In 2023, 4% of U.S. public water systems violated a health-based drinking water standard.
- In 2023, 93% of U.S. enforcement-priority systems were small systems serving 3,300 people or fewer.
- More than 20% of more than 2,100 sampled U.S. private domestic wells contained at least one contaminant at a potential-health-concern level.
- About 43 million people, or 15% of the U.S. population, use private wells for drinking water.
- Arsenic exceeded the EPA maximum contaminant level in approximately 11% of 7,580 evaluated U.S. domestic wells.
- Radon-222 exceeded 300 pCi/L in approximately 75% of evaluated U.S. domestic wells.
- In the 2014 U.S. model, drinking-water exposure was associated with 1.13 million domestically acquired infectious waterborne illnesses.
- In the same 2014 model, drinking-water exposure was associated with approximately 47,700 hospitalizations in the United States.
- In the 2014 U.S. model, drinking-water-associated illness generated an estimated $1.39 billion in direct emergency and hospital care costs.
- Norovirus accounted for 53% of illnesses associated with drinking water in the 2014 U.S. model.
- During 2015–2020, enteric illness outbreaks primarily linked to wells represented approximately half of reported U.S. cases.
Contents
- Global drinking water safety access statistics
- U.S. public drinking water compliance data
- Private well drinking water safety statistics
- Waterborne illness and drinking water health outcomes
- Drinking water outbreaks and pathogen statistics
- Treatment, wastewater and drinking water safety trends
Global Drinking Water Safety Access Statistics
The WHO/UNICEF Joint Monitoring Programme defines safely managed drinking water as an improved source on premises, available when needed and free from faecal and priority chemical contamination. This is a service-level estimate, not a direct census of every household’s water quality.
In 2022, 73% of the global population used safely managed drinking water services, leaving 27%, or 2.2 billion people, without that level of service. The estimate covered 142 countries and six of eight Sustainable Development Goal regions. WHO, Water supply, sanitation and hygiene monitoring
| Population or service category | 2022 estimate | Definition or scope |
|---|---|---|
| Global population using safely managed services | 73% | Improved source on premises, available when needed and free from faecal and priority chemical contamination |
| Rural population using safely managed services | 62% | Global rural population |
| Urban population using safely managed services | 81% | Global urban population |
| People lacking safely managed services | 2.2 billion | JMP estimate, not a direct contamination census |
Among those lacking safely managed service in 2022, 1.5 billion had basic services outside the home, services that were not always available or services that were unsafe. Another 292 million people used limited services requiring more than a 30-minute round trip to collect water, 296 million used unimproved sources such as unprotected wells or springs, and 115 million collected untreated water directly from rivers, lakes or similar surface sources.
The same source estimated that 25% of the global population, or 2.0 billion people, lacked basic household hygiene services in 2022. Hygiene is related safety context rather than the drinking-water service metric itself.
U.S. Public Drinking Water Compliance Data
EPA compliance records describe active public water systems and reported violations during calendar year 2023. “No reported violations” does not prove that every contaminant was absent, while monitoring and reporting failures are not direct estimates of unsafe water.
The United States had 148,541 active public water systems in 2023. Of these, 107,559 systems, or 72%, had no reported drinking-water-standard violations, while 40,982 systems, nearly 28%, violated at least one standard. EPA, Providing Safe Drinking Water in America: 2023 National Public Water Systems Compliance Report
| 2023 U.S. public-system measure | Systems | Share or definition |
|---|---|---|
| Active public water systems | 148,541 | National compliance dataset |
| No reported drinking-water-standard violations | 107,559 | 72% |
| At least one drinking water standard violation | 40,982 | Nearly 28% |
| Health-based standard violation | 6,045 | 4%; exceedance or treatment-technique failure |
| Monitoring or reporting failure | 29,703 | 20%; information-compliance measure |
EPA recorded 5,018 systems, or 3.4%, as enforcement priorities during at least one quarter of 2023. The threshold was a score of 11 or higher based on violation seriousness and duration.
Small systems serving 3,300 people or fewer accounted for 4,667, or 93%, of enforcement-priority systems. Agencies initiated at least one formal enforcement action at 2,398 systems and at least one informal enforcement action at 27,149 systems, while 24,819 systems were reported as returned to compliance after correcting violations.
Private Well Drinking Water Safety Statistics
Private wells are not represented by the same national compliance system used for public water systems. USGS findings distinguish detections, potential-health-concern levels and maximum contaminant level exceedances, and the domestic-well datasets were not designed as statistically representative national occurrence surveys.
About 43 million people, or 15% of the U.S. population, use drinking water from private wells. In a separate USGS summary of more than 2,100 sampled private domestic wells, more than 20% contained at least one contaminant at a potential-health-concern level. USGS, Water Quality of Potential Concern in US Private Wells
| Contaminant or finding | Result in evaluated domestic wells | Important qualification |
|---|---|---|
| Arsenic above 10 µg/L | Approximately 11% of 7,580 wells | Retrospective dataset, not a national probability sample |
| Nitrate above 10 mg/L | Approximately 8% of 3,465 wells | Same dataset limitation |
| Uranium-238 above 30 µg/L | Approximately 4% | Same dataset limitation |
| Radon-222 above 300 pCi/L | Approximately 75% | Potential standard under review, not a final federal MCL in the source |
| Radon-222 above 4,000 pCi/L | Approximately 9% | Potential standard under review |
The USGS reported that total mercury and fluoride each exceeded evaluated MCLs in fewer than 1% of domestic wells, and anthropogenic organic contaminants exceeded an MCL in fewer than 1% of all evaluated wells. Many organic contaminants had no MCL in the evaluation. USGS, The chemical quality of self-supplied domestic well water in the United States
Detection rates can be higher than exceedance rates because detection only means that a compound was measured. Atrazine was detected in 24% of evaluated wells, the highest rate among 28 organic contaminants studied; simazine and metolachlor were each detected in approximately 9%, MTBE in 6% and chloroform in 5%.
Waterborne Illness and Drinking Water Health Outcomes
CDC researchers modeled the 2014 U.S. burden by exposure route. Drinking-water exposure included drinking, washing and showering, so these results should not be interpreted as ingestion-only outcomes.
The 2014 estimate attributed 1.13 million domestically acquired infectious waterborne illnesses to drinking-water exposure, with a 95% credible interval of 255,000 to 3.54 million. Drinking water represented 16% of the study’s 7.15 million estimated infectious waterborne illnesses across exposure routes.
| 2014 drinking-water outcome | Estimate | 95% credible interval |
|---|---|---|
| Emergency-department visits | 31,600 | 4,070–133,000 |
| Hospitalizations | 47,700 | 24,600–72,800 |
| Deaths | 3,300 | 1,630–5,180 |
| Direct emergency and hospital care costs | $1.39 billion | $364 million–$4.81 billion |
Drinking water accounted for 40% of modeled waterborne-illness hospitalizations and 50% of modeled deaths. Its associated direct-care costs represented 42% of combined direct costs across the study’s water exposure routes. CDC Emerging Infectious Diseases, Estimating Waterborne Infectious Disease Burden by Exposure Route, United States, 2014
Norovirus accounted for 53% of illnesses associated with drinking water in the model. Nontuberculous mycobacteria accounted for 73% of drinking-water-associated hospitalizations and 78% of associated deaths, while the study estimated $3.33 billion in total direct waterborne-disease costs across all exposure routes; NTM represented 46% and Legionnaires’ disease 12% of that total.
Drinking Water Outbreak and Pathogen Statistics
Reported outbreaks and modeled burden answer different questions. Outbreak surveillance depends on detection and reporting, whereas burden models estimate illnesses and outcomes that may not be recognized as part of an outbreak.
During 2015–2020, enteric illness outbreaks primarily linked to wells represented approximately half of reported cases in the CDC drinking-water outbreak surveillance context. This does not mean that half of all private-well illness occurred in that period. CDC MMWR, Surveillance of Waterborne Disease Outbreaks Associated with Drinking Water—United States, 2015–2020
Historically, one-third of reported U.S. drinking-water disease outbreaks during 1971–2008 were linked to private wells. Surveillance methods and reporting changed across that period, so the historical share is not a current national rate. CDC Emerging Infectious Diseases, Estimating Waterborne Infectious Disease Burden by Exposure Route, United States, 2014
For broader context, the cited CDC estimate puts annual U.S. waterborne disease burden at 7.15 million illnesses, 118,000 hospitalizations and 6,630 deaths across all water exposure routes. The drinking-water component is therefore a modeled subset, not the total burden.
Drinking Water Treatment, Wastewater and Safety Trends
Wastewater and premise plumbing provide related context but are not direct household drinking-water safety scores. In 2022, 42% of household domestic wastewater was not safely treated before discharge, equivalent to an estimated 113 billion cubic meters.
About 45% of household wastewater lacking safe treatment was attributed to inadequate blackwater and greywater collection systems. These WHO/UNICEF estimates describe environmental treatment and collection conditions, not the performance of a drinking-water filter or public water utility. WHO, Water supply, sanitation and hygiene monitoring
The 2014 U.S. exposure-route model estimated 5.61 million illnesses from recreational water, 1.13 million from drinking water and 407,000 from nonrecreational nondrinking water. It estimated 552,000, 31,600 and 17,200 emergency-department visits for those routes respectively, plus 42,300, 47,700 and 27,900 hospitalizations.
| Exposure route, United States | Illnesses, 2014 | Hospitalizations, 2014 | Deaths, 2014 |
|---|---|---|---|
| Recreational water | 5.61 million | 42,300 | 1,290 |
| Drinking water | 1.13 million | 47,700 | 3,300 |
| Nonrecreational nondrinking water | 407,000 | 27,900 | 2,040 |
The same model estimated 1,290 recreational-water deaths, 3,300 drinking-water deaths and 2,040 nonrecreational-nondrinking-water deaths. The United States also has approximately 6 million miles of premise plumbing inside buildings, a related exposure setting rather than a direct safety score. CDC Emerging Infectious Diseases, Estimating Waterborne Infectious Disease Burden by Exposure Route, United States, 2014