Environments and Contaminants - Drinking Water Contaminants
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).
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Indicators
Estimated percentage of children ages 0 to 17 years served by community water systems that did not meet all applicable health-based drinking water standards, 1993-2021 (Indicator E7)
Web update: 2023
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- 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.
- The estimated percentage of children served by community drinking water systems that did not meet all applicable health-based standards declined from 20% in 1993 to about 5% in 2001. Since 2002, this percentage has fluctuated between 5% and 12%, and was 7% in 2021.
- The estimated percentage of children served by community drinking water systems that did not meet surface water treatment standards has varied between 1% and 5% following the implementation of new regulatory requirements in 2002, and was 5% in 2021.
- Total coliforms indicate the potential presence of harmful bacteria associated with infectious illnesses. The estimated percentage of children served by community drinking water systems that did not meet the health-based standard for total coliforms was about 10% in 1993 and 0.4% in 2021.
- A new standard for disinfection byproducts was adopted in 2001. The estimated percentage of children served by community water systems that had violations of the disinfection byproducts standard was about 3% in 2003 and 1% in 2021.
Estimated percentage of children ages 0 to 17 years served by community water systems with violations of drinking water monitoring and reporting requirements, 1993-2021 (Indicator E8)
Web update: 2023
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- 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.
- Between 1993 and 2021, the estimated percentage of children served by community water systems that had at least one monitoring and reporting violation fluctuated between about 10% and 23%, and was 11% in 2021.
- In 1993, approximately 7% of children served by community water systems lived in an area with significant monitoring and reporting violations for lead and copper. This figure dropped to about 5% in 2021.
- The estimated percentage of children served by community water systems with at least one chemical and radionuclide monitoring violation varied between 4% and 8% from 1993 to 2019, and then dropped down to 0.6% in 2021.
About the Drinking Water Contaminants Indicators
Indicators E7 and E8 present information about children served by community water systems that did not meet all health-based drinking water standards (E7) or failed to adhere to monitoring and reporting requirements (E8). The data are from a database that compiles drinking water violations reported by public water systems.
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 contaminant 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.
Indicators E7 and E8 present data on children served by community water systems that did not meet all health-based drinking water standards or failed to adhere to monitoring and reporting requirements from EPA's Safe Drinking Water Information System, Federal Version (SDWIS/FED).
More information about drinking water contaminants and indicators E7 and E8 is provided in the Drinking Water section of America's Children and the Environment, Third Edition (pdf) .
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 from various precursor database systems that have violation and inventory 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