Environments and Contaminants - Drinking Water Contaminants
Drinking water contaminants, including microbes and chemicals, may impact children's health. Children, especially formula-fed infants, drink more water relative to their body weight than adults.
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Indicators
E7: Children served by community water systems that did not meet drinking water standards
Web update: 2025
Key Information
- In 2023, about 7% of children were served by community drinking water systems that did not meet all health standards. This percentage has declined since 1993, when it was almost 20%.
- In 2023, the most common health-based violations for drinking water systems were related to water treatment. An estimated 4% of children were impacted by violations of EPA’s surface water treatment rules, which require systems to filter and disinfect water supplies to remove disease-causing microbes. An estimated 1.5% of children were impacted by violations of EPA’s rules to limit exposure to harmful byproducts that result from disinfecting water supplies.
- In 1993, the most common health-based violation for drinking water systems was for total coliforms, which indicate the potential presence of harmful bacteria associated with disease. At that time, an estimated 10% of children were impacted by violations of EPA’s Total Coliform Rule. This number has decreased to less than 1% of children in 2023.
Data Characterization
Data for this indicator are obtained from EPA's database to which states are required to report public water system violations of National Primary Drinking Water Regulations (NPDWR).
All violations of health-based standards are supposed to be reported to the database; however, it is known that not all violations are reported and the magnitude of underreporting is not known.
Some drinking water standards have been changed over time to increase the level of public health protection; therefore, as noted on the figure, some types of violations in more recent years are not strictly comparable to violations in earlier years.
Non-public drinking water systems, such as private wells, are not represented in the database. In 2015, about 13% of the U.S. population was served by non-public water systems.
E8: Children served by community water systems with violations of drinking water monitoring and reporting requirements
Web update: 2025
Key Information
- In 2023, about 18% of children were served by community water systems with at least one monitoring or reporting violation. Between 1993 and 2023, this number fluctuated between 10% and 24%.
- In 2023, the most common monitoring and reporting violations were for the disinfection byproducts and lead and copper rules. In 2023, approximately 6% of children served by community water systems lived in an area with monitoring and reporting violations for each of these rules.
Data Characterization
Data for this indicator are obtained from EPA's database to which states are required to report public water system violations of National Primary Drinking Water Regulations (NPDWR).
Monitoring and reporting violations occur when a water system does not monitor, does not report monitoring results, or was late in reporting results. Such violations in monitoring and reporting may mean that some health-based violations were not reported; this could cause the percentages shown in Indicator E7 to be underestimated.
Some drinking water standards have been changed over time to increase the level of public health protection; therefore, as noted on the figure, some types of violations in more recent years are not strictly comparable to violations in earlier years.
Non-public drinking water systems, such as private wells, are not represented in the database. In 2015, about 13% of the U.S. population was served by non-public water systems.
About the Drinking Water Contaminants Indicators
Several types of drinking water contaminants may be of concern for children's health. Examples include microorganisms, (e.g., E. coli, norovirus, and Giardia), inorganic chemicals (e.g., lead, arsenic, nitrates, and nitrites), organic chemicals (e.g., atrazine, glyphosate, trichloroethylene, and tetrachloroethylene), and disinfection byproducts (e.g., chloroform). These contaminants and others may be associated with increased risk of a range of diseases in children, including acute diseases such as gastrointestinal illness, developmental effects such as learning disorders, endocrine disruption, and cancer.
EPA sets enforceable drinking water standards for public water systems. The drinking water standards include maximum levels and treatment technique requirements for more than 90 chemical, radiological, and microbial contaminants, designed to protect people, including sensitive populations such as children, against adverse health effects. Microbial contaminants, lead, nitrates and nitrites, arsenic, disinfection byproducts, pesticides, and solvents are among the contaminants for which EPA has set health-based standards.
For historic and contextual information about drinking water contaminants and these indicators, see the Drinking Water section of America's Children and the Environment, Third Edition (pdf) .
Data Sources and Methods – Drinking Water Contaminants
EPA's Safe Drinking Water Information System, Federal Version (SDWIS/FED) provides information on violations of drinking water standards. Public drinking water systems in the United States are required to monitor the presence of certain individual contaminants at specific time intervals and locations to assess whether they are complying with drinking water standards. When a violation of a drinking water standard is detected, the public water system is required to report the violation to the state, which in turn reports to the federal government. All health-based violations are compiled in SDWIS/FED. SDWIS/FED was created in 1995 and includes data going back to 1976.
Indicators E7 and E8 use the SDWIS/FED data to present the percentage of children ages 0 to 17 years served by community water systems that either did not meet health-based drinking water standards, or that had some violation of monitoring or reporting requirements. For the most part, both indicators use a consistent set of standards for comparison over the years presented—there are some exceptions from revisions to various water standards. Breaks in the trend lines represent significant revisions to water standards for surface water treatment. Revisions to other standards had only minimal impacts on the indicator values. U.S. Census data are used to estimate the total number of children served by community water systems.
- Detailed Methods for Indicators E7 and E8 (pdf)
- Safe Drinking Water Information System Federal Version (SDWIS/FED) (pdf)
- Metadata for Census: Intercensal and Postcensal Data
Related Links
- U.S. EPA: Drinking Water Regulations and Contaminants
- U.S. EPA: Ground Water and Drinking Water
- U.S. EPA: Safe Drinking Water Information System, Federal Version (SDWIS/FED)
- U.S. EPA: Total Coliform Rule
- U.S. EPA: Private Drinking Water Wells
- U.S. EPA: Lead in Private Well Water and its Impact on Children’s Health
- U.S. EPA: Lead and Copper Rule
- Centers for Disease Control and Prevention (CDC): Drinking Water