Drinking Water

At a glance

The Tracking Network has data and information about the levels of several contaminants that can be found in drinking water. These contaminants were selected because they occur more frequently in drinking water at levels that may be of public health significance.

Woman drinking glass of water

We Track That

About 90% of people in the United States get their water from a community water system. The U.S. Environmental Protection Agency (EPA) sets regulations for treating and monitoring community drinking water. National and state drinking water protection programs play a critical role in ensuring high-quality drinking water and in protecting the public’s health.

The drinking water data used in the Tracking Network are gathered as part of the water quality monitoring requirements set by the EPA and state agencies. They are not gathered specifically to assess the level of exposure or to track changes in water quality over time. However, they can be used to determine the potential for public health impacts from contaminant levels of concern.

Did you know?‎

Tracking Network data are the only set of consistent drinking water quality data nationwide.

Several issues were considered in the development of the Tracking Network's drinking water contaminants measures. The main issues include the following.

  • Exposure patterns
  • Monitoring requirements/sampling frequency
  • Censored values
  • Drinking water quality standards/Maximum Contaminant Levels (MCL)

Types of Data

The indicators for drinking water describe public water use and the levels of various contaminants in public water supplies. These data indicate the potential for public health effects from contaminant levels of concern.

This indicator shows the number of community water systems per state and the number of people receiving water from those community water systems. The data comes from state grant recipients. It can be used to estimate the population potentially exposed to contaminants in community water systems.

The Tracking Network has data on regulated and unregulated contaminants in drinking water from community systems.

Regulated Drinking Water Contaminants

Data for these measures come from health departments funded by the Tracking Program. For each contaminant, you can determine the following.

  • Distribution of level of contaminant in finished drinking water
  • Potential for exposure to the contaminant in finished drinking water
  • Level of contaminant in finished drinking water

Regulated Drinking Water Contaminants

Unregulated Drinking Water Contaminants

These measures provide information on

  • water systems where unregulated contaminants were detected.
  • where PFOA and PFOS were in exceedance of EPA health advisory level.
  • water systems where samples were taken but no chemicals were detected.

Unregulated Drinking Water Contaminants

Access the Data

Use the Data Explorer to create custom maps, tables, and charts.

View data in simple Quick Reports.

Get machine-readable data from the Application Program Interface (API).

Data in Action

Drinking water data on the Tracking Network can be used for the following actions.

  • Determine how well community water systems produce high-quality water
  • Assess potential for exposure to drinking water contaminants
  • Estimate potential long-term exposure to drinking water contaminants