• Dhathri Srungaram

How Tap Water is Regulated in the U.S.

Around 94% of the US population gets at least some of their water from a community water system (CWS).

In the US, tap water is regulated by the EPA (Environmental Protection Agency) whereas bottled water is regulated by the FDA (Food and Drug Administration). In 1974, the Safe Drinking Water Act (SDWA) was passed by Congress. The act allows the EPA to:

  • Establish minimum standards to protect tap water and require owners of public water supplies to comply with these standards.

  • Establish minimum standards for state programs to protect underground sources of drinking water.

  • Set rules and schedules regarding water testing.

Furthermore, the SDWA gives states the ability to enforce their own safety standards in addition to the minimums set by the EPA.

The EPA regulates over 90 water contaminants, providing a legal limit for drinking water. This legal limit reflects “the level that protects human health and that water systems can achieve using the best available technology.” The EPA uses the Unregulated Contaminant Monitoring Rule (UCMR) to monitor for priority unregulated contaminants in drinking water every 5 years. This program was developed in conjunction with the Contaminant Candidate List (CCL), which is used to help select contaminants for the program. The CCL is composed of contaminants that, “are not regulated by the National Primary Drinking Water Regulations (NPDWR), are known or anticipated to occur at public water systems, [and] may warrant regulation under the SDWA.”

In order to determine if a contaminant should be regulated, the EPA considers three things:

  • The contaminant may have a negative impact on human health

  • There is a chance the contaminant will occur in a public water system

  • The contaminant is determined to create a health risk for people who use a public water system

If the EPA decides to regulate the contaminant, it then “starts the rulemaking process to establish the NPDWR." If the decision is made not to regulate the contaminant, then the EPA may choose to create a health advisory. This is a non-enforceable limit that serves as a guide for local, state, and federal authorities.

If the EPA were to issue federal water restrictions, a water authority may choose to pay a fine and request additional time to meet the new guideline set by the EPA. If a public water authority does this, then they are required to notify customers, and their water safety reports should be made available as a public record on their website. Water companies are required to provide you with a Consumer Confidence Report (CCR) every year. You can access your CCR through the EPA’s CCR tool.

Knowing the contaminants in the tap water of any city can help residents understand what steps they need to take to keep themselves safe from water-related health issues. Apart from the EPA, there are other resources available to help people learn about their tap water. Third-party environmental groups like the Environmental Working Group (EWG) and My Tap Water can help determine if your water is considered contaminated by EPA standards since it can be cumbersome to comb through the water safety reports issued by your water provider. It’s important to note that the EWG tracks contaminants that the EPA does not regulate and have not been shown to have a negative impact on humans.


Speaking Plainly:

  • The EPA regulates tap water and the FDA regulates bottled water.

  • The SDWA was established to protect public drinking water, and once a contaminant is deemed dangerous by the UCMR and the CCL, the EPA establishes a rule with the NPDWR.

  • Use databases like EWG and My Tap Water to determine what contaminants exist in your water supply