Drinking Water Violations

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Indicator of the presence of health-related drinking water violations. 'Yes' indicates the presence of a violation, 'No' indicates no violation. The 2024 Annual Data Release used data from 2022 for this measure.

Ensuring the safety of drinking water is important to prevent illness, birth defects, and death.1 Other health problems have been associated with contaminated water, including nausea, lung and skin irritation, cancer, infection, and birth defects.2,3 An increase in drinking water violations has also been shown to increase health care expenditures.4 Between 3 and 10% of community water systems experience a violation each year.5 

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Data and methods

Data Source

Safe Drinking Water Information System

From EPA:

The Safe Drinking Water Information System (SDWIS) contains information about public water systems and their violations of EPA's drinking water regulations, as reported to EPA by the states. These regulations establish maximum contaminant levels, treatment techniques, and monitoring and reporting requirements to ensure that water systems provide safe water to their customers.

Website to download data

Key Measure Methods

Drinking Water Violations is an indicator

Drinking Water Violations has only two values: Yes and No. A “Yes” indicates that at least one community water system in the county received at least one health-based violation during the specified time frame. A “No” indicates that there were no health-based drinking water violations in any community drinking water system in the county.

The method for calculating Drinking Water Violations has changed

With the 2018 Annual Data Release, the data source for this measure changed to the Safe Drinking Water Information System Federal Reports Advanced Search. Beginning in 2016, the Health Snapshots reported Drinking Water Violations as a Yes/No variable to indicate the presence or lack of a violation in any community water system. Previously, this measure provideded an estimate of the percentage of the county population impacted by any health-based drinking water violations throughout the year. However, we were advised by local agencies that it is difficult to determine the exact population impacted by any specific violation, as water systems have water system partnerships with other jurisdictions.

Caution should be used when comparing these estimates across states

Data may not be comparable across states due to variation in database quality and state-level enforcement. 

Caution should be used when comparing these estimates across years

Data may not be comparable across years due to changes in regulations, monitoring, and drinking water standards.

Measure limitations

There are a number of limitations associated with this measure: 

  • The number of violations within each system is not taken into account, and estimates are not available for the number of people who consume infected water or get ill from consumption.
  • Not all violations are equivalent; some violations occur but are addressed quickly, while some violations can linger for years. Violations could be slightly over or much higher than the Maximum Contaminant Level. 
  • Testing date, frequency, location, and type can play a role in violation detection.
  • This measure only includes data on community water systems and does not include private wells.
  • The required reporting of water quality tests is often based on annual and/or system-wide averages of individual sampling results. For example, Community Water Systems (CWS) may be required to sample at four different locations but report only the average.
  • Violations identified as health-based have changed over time.

Can This Measure Be Used to Track Progress

This measure is not appropriate for measuring progress. 

Finding More Data

Disaggregation means breaking data down into smaller, meaningful subgroups. Disaggregated data are often broken down by characteristics of people or where they live. Disaggregated data can reveal inequalities that are otherwise hidden. These data can be disaggregated by:

  • Subcounty Area

Drinking water violations can be measured through many local data sources. In addition, specific data on water systems such as type of violation, containment, and date of violation can be found with the US Environmental Protection Agency. 


1 Craun GF, Brunkard JM, Yoder JS, Roberts VA, Capenter J, et al. Causes of outbreaks associated with drinking water in the United States from 1971 to 2006. Clinical Microbiology Reviews. 2010;23(3):507-528.

2 Centers for Disease Control and Prevention (CDC). Preventing Waterborne Germs at Home. 2023. Accessed February 27, 2024. https://www.cdc.gov/healthywater/drinking/preventing-waterborne-germs-at-home.html

3 Hunter PR, MacDonald AM, Carter RC. Water supply and health. Public Library of Science (PLOS) Medicine. 2010;7(11). 

4 Alzahrani F, Collins A R, Erfanian E. Drinking water quality impacts on health care expenditures in the United States. Water Resources and Economics. 2020;32:100162.

5 Allaire M, Wu H, Lall U. National trends in water quality violations. Proceedings of the National Academy of Sciences. 2018;115(9):2078-2083.

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