Water and chemicals from firefighting foam and other sources

PFAS may enter our environment and drinking water through the manufacturing, use, and disposal of PFAS-containing products. In April 2024, the EPA set Maximum Contaminant Levels (MCLs) for six PFAS: PFOA, PFOS, PFNA, PFHxS, PFBS, and GenX Chemicals. MCLs are legally enforceable standards that public water systems have to meet. These standards account for health information, available testing technology, treatment techniques, and costs. This page has information for water consumers as well as water providers to learn more about these chemicals.

• If your water system is not listed, it’s possible they tested for PFAS but did not participate in the department's sampling programs.
• If your water system has tested for PFAS, they might have their results listed on their website. You can also contact your system directly to ask about test results.
• If your system has not tested for PFAS or signed up to test for PFAS, encourage them to do so through the PFAS Grant Program.

If you get drinking water from a private well, have the well tested for PFAS. You can request free testing through the PFAS Grant Program. For help interpreting lab results, please contact the department's toxicology hotline: CDPHE_Toxcall@state.co.us｜303-692-2606.

The EPA’s Maximum Contaminant Levels (MCLs) for PFAS in drinking water include levels for:

• PFOA at 4.0 parts per trillion (ppt).
• PFOS at 4.0 ppt.
• PFNA at 10 ppt.
• PFHxS at 10 ppt.
• GenX at 10 ppt.
• A hazard index of 1 (unitless) to account for mixtures of PFAS.

These drinking water MCLs are set to protect all people, including sensitive populations and critical life stages such as pregnancy or early childhood, from negative health impacts as a result of lifetime exposure to PFAS in drinking water. The lower the levels of PFAS, the lower the risk. There are ways for individuals who are concerned about PFAS in their drinking water or from other sources to reduce exposure. To learn more, please visit the PFAS and your health webpage.

The department is partnering with water systems to assess PFAS levels, inform the public about PFAS levels in tap water, and take steps to reduce PFAS levels in tap water.

We strongly recommend that all public water systems (even those without PFAS detections) keep their customers updated on their PFAS-related activities, including all sampling results (even if PFAS aren't detected) and any potential PFAS reduction steps. Both the department and water systems should request that the laboratory provide data to the lowest level they are capable of detecting. We maintain a list of certified labs approved for PFAS analysis using Method 533 or Method 537.1.

When PFAS levels in tap water exceed the EPA’s MCLs, the department recommends that the water system inform the public. The information provided should include the sample results and an explanation of their significance. If you are a water system and need further assistance on this, please use the department’s consumer drinking water notice template. The department also offers a Spanish version of the consumer drinking water notice template.

From 2023 to 2025, large public water systems and some smaller ones must monitor for 29 PFAS and lithium under the EPA’s Unregulated Contaminant Monitoring Rule (UCMR). EPA uses the UCMR to collect data on contaminants in drinking water that do not have health-based standards. These data help EPA determine whether future health research and/or regulation is needed.

UCMR test results are available on the EPA’s website. Water systems must also share information with customers about contaminants they detect.