Skip to main content

PFAS: A Word About Drinking Water Guidelines

For a PDF version of this factsheet, click here.

Are PFAS regulated in drinking water?

PFAS (per- and polyfluoroalkyl substances) are currently not regulated under the Safe Drinking Water Act. This means there are no federal drinking water standards and public water supplies do not have to test or treat their water for PFAS under federal law.

The U.S. Environmental Protection Agency (EPA) has set a non-enforceable health-based guideline level of 70 parts per trillion (ppt) for PFOA and PFOS, individually or combined.

However, many scientists and regulators believe this guideline is not protective enough of human health. As a result, some states have developed their own guideline levels for PFAS that are stricter than EPA’s, and some have set, or are in the process of setting, enforceable standards.

Although guideline levels are not enforceable, meaning water utilities are not required to test or treat the water, they do offer some protection.

13 states with drinking water guidelines that are more restrictive than EPA’s.

water from a tap

Why do guidelines vary?

Guideline levels are created when regulators, after reviewing the science, calculate a level of exposure below which health effects are not expected to occur. Regulators consider different types of evidence and factors when developing guideline levels:

  • Studies linking exposure to PFAS with various health effects (for instance, effects on the immune system, liver, or mammary gland development).
  • The impact on vulnerable populations such as infants or pregnant women.
  • How much water people drink in a day.
  • How much exposure likely comes from drinking water versus diet and consumer products.
  • Molecular studies that show what happens to PFAS after the chemicals enter the body.

Although some variation is expected among the different state guideline levels, more recent guidelines are being set at similarly lower levels

Learn more: