Water contamination statistics span access, measured contaminants, outbreaks and health outcomes. The figures below distinguish global service estimates from U.S. surveillance, disease models and older domestic-well research.
Key Water Contamination Statistics
The most broadly useful figures are:
- In 2024, 74% of the global population used safely managed drinking-water services.
- In 2024, 2.1 billion people worldwide lacked safely managed drinking-water services.
- Between 2015 and 2024, 961 million people worldwide gained access to safely managed drinking water.
- From 2015 to 2024, global safely managed drinking-water coverage rose from 68% to 74%.
- In 2024, 106 million people worldwide drank surface water from lakes, ponds, rivers or streams.
- In 2024, safely managed drinking-water coverage was 21% in least developed countries.
- If current trends continue, 38 countries are projected to reach universal safely managed access by 2030.
- In 2014, an estimated 7.15 million domestically acquired waterborne illnesses occurred in the United States.
- In 2014, an estimated 601,000 U.S. emergency-department visits were attributed to waterborne transmission.
- In 2014, an estimated 6,630 U.S. deaths were attributed to waterborne transmission.
- In 2014, selected domestically acquired waterborne disease had an estimated $3.33 billion in direct U.S. health-care costs.
- During 2013–2014, 42 drinking-water-associated outbreaks were reported in the United States.
- During 2013–2014, the reported U.S. drinking-water outbreaks caused at least 1,006 illnesses.
- In the evaluated domestic-well dataset, arsenic exceeded the U.S. EPA maximum contaminant level in about 11% of wells.
- In the evaluated domestic-well dataset, about 75% of wells exceeded 300 pCi/L for radon-222.
- EPA estimates approximately 4 million U.S. lead service lines.
- EPA estimates that its final PFAS drinking-water rule could reduce exposure for approximately 100 million people in the United States.
Contents
- Global water contamination and safely managed drinking-water access
- Water contamination data by service level and geography
- U.S. waterborne illness and health-care costs
- Drinking-water outbreaks and contamination events
- Private-well and groundwater contamination
- Lead and PFAS drinking-water infrastructure
Global Water Contamination Statistics and Safely Managed Drinking-Water Access
The WHO/UNICEF safely managed indicator is not a direct laboratory prevalence rate. It means an improved source is on premises, available when needed and free from faecal and priority chemical contamination.
In 2024, 74% of the global population used safely managed drinking-water services, while 2.1 billion people lacked that level of service. The WHO/UNICEF estimate covered 72% of the global population with data and may include imputation.
| Global measure | Period | Estimate |
|---|---|---|
| Safely managed drinking-water coverage | 2024 | 74% of population |
| People lacking safely managed service | 2024 | 2.1 billion |
| People with basic but not safely managed service | 2024 | 1.4 billion |
| Limited service, requiring over 30 minutes to collect | 2024 | 287 million |
| Unimproved drinking-water service | 2024 | 302 million |
| Surface-water use | 2024 | 106 million |
Source: Progress on household drinking water, sanitation and hygiene 2000–2024: special focus on inequalities. These are JMP service-level estimates, not contaminant concentration measurements.
From 2015 to 2024, global safely managed coverage rose from 68% to 74%, and 961 million people gained access. Rural coverage rose from 50% to 60%, while urban coverage was 83% in both 2015 and 2024; the stable urban aggregate does not mean every urban population had stable contamination conditions.
The number of people using surface water for drinking decreased by 61 million between 2015 and 2024. In 2024, 31 countries had universal safely managed access, defined in the report as more than 99% coverage, and the JMP had estimates for 160 countries.
The 2024 report also states that comparable WASH estimates are produced for 235 countries, areas and territories. Earlier WHO reporting estimated that in 2022, 6 billion people used safely managed services, 1.5 billion used basic services, 292 million used limited services, 296 million collected water from unprotected wells and springs, and 115 million collected untreated surface water.
Source: Drinking-water.
Water Contamination Data by Service Level and Geography
Service-level comparisons show where safely managed access is most limited, but they should not be read as a map of contaminant concentrations. The groupings below follow the report’s regional and contextual classifications.
| Geographic group | Safely managed coverage, 2024 |
|---|---|
| Least developed countries | 21% |
| Fragile contexts | 30% |
| Small island developing states | 76% |
| Northern Africa and Western Asia | 75% |
| Eastern and South-Eastern Asia | 75% |
Source: Progress on household drinking water, sanitation and hygiene 2000–2024: special focus on inequalities. Regional aggregates do not imply that all sources within a group met identical contaminant thresholds.
In 2024, 89 countries had universal access to at least basic drinking-water services, a less stringent benchmark than safely managed access. If current trends continue, 38 countries are projected to reach universal safely managed access by 2030; this is a trend-based forecast, not an observed future result.
The distinction matters for interpretation: an improved source within a 30-minute round trip can qualify as basic service, while safely managed service adds on-premises availability, reliability and freedom from faecal and priority chemical contamination.
U.S. Waterborne Illness Statistics and Health-Care Costs
A CDC Emerging Infectious Diseases study estimated the burden of selected infectious waterborne diseases in the United States in 2014. These are model-based estimates for selected diseases and exposure pathways, not a count of chemical-contamination illnesses.
| U.S. outcome | 2014 estimate |
|---|---|
| Domestically acquired waterborne illnesses | 7.15 million |
| Emergency-department visits | 601,000 |
| Hospitalizations | 118,000 |
| Deaths | 6,630 |
| Direct health-care cost | $3.33 billion |
Source: Estimate of Burden and Direct Healthcare Cost of Infectious Waterborne Disease in the United States. Direct costs cover emergency visits and hospitalizations and are not total societal costs.
The study estimated 4.67 million illnesses from otitis externa, 1.33 million from norovirus infection, 415,000 from giardiasis and 322,000 from cryptosporidiosis. It also estimated 96,000 domestically acquired waterborne respiratory illnesses and 2.33 million waterborne enteric illnesses in 2014.
For severe outcomes, nontuberculous mycobacterial infection accounted for an estimated 51,400 waterborne hospitalizations and 3,800 deaths. Legionnaires’ disease accounted for an estimated 995 deaths, while Pseudomonas pneumonia accounted for an estimated 730 deaths.
The source reports credible intervals around several disease estimates. The figures therefore describe modeled burden, and the disease categories should not be treated as direct measurements of contaminant levels in drinking water.
Drinking-Water Outbreak Statistics and Contamination Events
CDC surveillance recorded 42 drinking-water-associated outbreaks in the United States during 2013–2014 across 19 reporting states. These are reported events, so they may not capture unrecognized or unreported outbreaks.
The 42 outbreaks caused at least 1,006 illnesses, 124 hospitalizations and 13 deaths. The word “at least” reflects incomplete case ascertainment in outbreak reporting.
| Reported outbreak measure | 2013–2014 count |
|---|---|
| Drinking-water-associated outbreaks | 42 |
| Illnesses | At least 1,006 |
| Hospitalizations | 124 |
| Deaths | 13 |
| Outbreaks associated with Legionella | 24 |
Legionella was implicated in 130 reported outbreak-associated illness cases and 109 hospitalizations, and it was associated with all 13 deaths in this surveillance dataset. Those etiologic counts include confirmed and suspected etiologies and do not represent all U.S. waterborne deaths.
Four outbreaks involving chemicals or toxins accounted for 499 reported cases. This is an outbreak-specific count, not a national estimate of chemical exposure or chemical-contamination disease.
Private-Well and Groundwater Contamination Statistics
The USGS study of self-supplied domestic well water used a retrospective dataset published in 2006. It was not designed as a statistically representative national sample, so the percentages describe evaluated wells rather than every U.S. private well.
| Constituent or measure | Evaluated-well result | Threshold or interpretation |
|---|---|---|
| Arsenic | About 11% exceeded | EPA MCL: 10 µg/L |
| Nitrate | About 8% exceeded | EPA MCL: 10 mg/L |
| Uranium-238 | About 4% exceeded | EPA MCL: 30 µg/L |
| Radon-222 | About 75% exceeded | 300 pCi/L potential standard under review |
| Radon-222 | About 9% exceeded | 4,000 pCi/L potential standard under review |
| Total mercury and fluoride | Each below 1% exceeded threshold | Exact percentages not stated |
Source: The chemical quality of self-supplied domestic well water in the United States. The radon levels were potential standards under review, not final federal maximum contaminant levels.
Atrazine was detected in 24% of evaluated domestic wells. Detection is not the same as exceeding a health standard, and the study evaluated 28 organic contaminants.
All evaluated anthropogenically derived organic contaminants exceeded an MCL in fewer than 1% of wells overall, although several evaluated contaminants had no MCL. The denominator was not identical for every constituent, so these results should not be combined into a single national prevalence estimate.
Lead and PFAS Drinking-Water Contamination Statistics
Lead-service-line figures describe infrastructure inventories, not a direct estimate of lead concentration at every tap. EPA’s current estimate combines reported lead-containing lines with an estimate for unknown-material lines likely to contain lead.
| U.S. service-line measure | Estimate or reported count |
|---|---|
| EPA estimate of lead service lines | Approximately 4 million |
| State-reported lines containing lead, combining lead and galvanized lines requiring replacement | About 3 million |
| Unknown-material lines likely to contain lead | About 1 million |
Source: Service Line Inventory. Confirmed counts depend on state and primacy-agency inventory reporting.
EPA estimates that approximately 4 million lead service lines exist in the United States, including about 1 million unknown-material lines likely to contain lead. State-reported inventories confirmed about 3 million lines when lead and galvanized-requiring-replacement lines are combined.
For PFAS, EPA’s 2024 final drinking-water rule is expected to reduce PFAS exposure for approximately 100 million people in the United States. That figure is a projected population benefit, not a measured post-rule reduction.
Source: Final PFAS National Primary Drinking Water Regulation: Technical Overview. PFAS and lead figures include estimates, infrastructure counts and projections, so they should not be interpreted as observed outcome totals.