Drinking water violations

Indicator of the presence of health-related drinking water violations. Yes indicates the presence of a violation, No indicates no violation.
The 2019 County Health Rankings used data from 2017 for this measure.

Measure Tabs


Reason for Ranking

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, kidney, liver, and nervous system damage.[2,3]

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

In 2018, the County Health Rankings updated their data source to the Safe Drinking Water Information System Federal Reports Advanced Search. Beginning in 2016, the County Health Rankings reported the Drinking Water Violations as a Yes/No variable that indicates the presence or lack of a violation in any community water system. Previously, this measure indicated 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.

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 MCL. 
  • 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.

What is a violation?

Health-based violations include Maximum Contaminant Level, Maximum Residual Disinfectant Level and Treatment Technique violations.

Can This Measure Be Used to Track Progress?

This measure is not appropriate for measuring progress. 

Data Source

Years of Data Used


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.

Digging Deeper

AgeNot applicable
GenderNot applicable
RaceNot applicable
EducationNot applicable
IncomeNot applicable
Subcounty Areatrue

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 at the following website: https://www3.epa.gov/enviro/facts/sdwis/search.html.


[1] Gunther CF, 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 July 7, 2010. https://cmr.asm.org/content/23/3/507
[2] Safe Drinking Water. Centers for Disease Control. https://www.cdc.gov/safewater/disease.html
[3] Hunter PR, MacDonald AM, and Carter RC. Water Supply and Health. PLoS Med; 7 (11). Nov 9, 2010. 

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