MDH develops health-based rules and guidance to evaluate potential human health risks from exposures to chemicals in drinking water. A health-based guidance value (HBV) is the level of a contaminant that can be present in water and pose little or no health risk to a person drinking that water over a lifetime, including sensitive populations and those who are highly exposed.

MDH recently released revised HBVs for perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) in drinking water. MDH is evaluating how to incorporate the updated PFOS and PFOA guidance values into its risk assessment for PFAS in drinking water. For more information, visit Guidance Values and Standards for Contaminants in Drinking Water.

What activity is happening at the federal level?

The U.S. Environmental Protection Agency (EPA) released National Primary Drinking Water Regulation for PFOA, PFOS, PFNA, PFHxS, and GenX. This regulation includes a non-enforceable Maximum Contaminant Level Goal (MCLG) and an enforceable standard, or Maximum Contaminant Level (MCL).

An MCLG is the level of a contaminant in drinking water below which there is no known or expected risk to health. The MCLG is a non-enforceable, health-based level. The MCLs are enforceable standards and are based on MCLGs but also other factors such as available technology, treatment techniques, and costs.

The new MCLs are 4 parts per trillion (ppt) for PFOS and PFOA, and 10 ppt for PFNA, PFHxS, and GenX. Under the Safe Drinking Water Act, public water systems are required to meet MCLs for contaminants. Public water systems are not required to meet MCLGs.

EPA also released an enforceable limit for four PFAS (PFBS, PFHxS, GenX and PFNA) that would be evaluated in combination with each other using an approach called a Hazard Index. A hazard index is calculated by comparing a measured drinking water value with a standard.

Public water systems will have three years to test for PFAS and an additional two years before they are required to meet the new MCLs. EPA will accept past PFAS testing results from systems that participated in the Fifth Unregulated Contaminant Rule (UCMR5). MDH will seek to use existing PFAS sampling data as much as possible.

For more information about these federal activities, visit the EPA page, Per- and Polyfluoroalkyl Substances (PFAS).

How can I find out more about PFAS in my drinking water?

MDH has tested community water systems (CWSs) across the state for PFAS. Our Interactive Dashboard for PFAS Testing in Drinking Water shows CWSs' testing results and whether results are below or above available health-based guidance values.

MDH is evaluating how to incorporate the updated PFOS and PFOA guidance values into its risk assessment for PFAS in drinking water. After this evaluation is complete, the dashboard will be updated as needed.

Where can I go for more information or for communications resources?

The EPA page Per- and Polyfluoroalkyl Substances (PFAS) has up-to-date information about federal activities. There are also several factsheets available there with more information and frequently asked questions:

What about PFAS and private wells?

People using private wells can find information about PFAS risks, testing, and treatment at Per- and Polyfluoroalkyl Substances and Private Wells.

What are my options to reduce PFAS exposure?

If you have concerns about your health, you can take steps to reduce your potential exposure to PFAS from drinking water in your home. Visit PFAS and Home Treatment of Water for information about household drinking water treatment. Other ways to reduce PFAS exposure can be found at PFAS and Health.

What is Minnesota doing to address PFAS in the environment?

To learn more about other state efforts to address PFAS, visit the Minnesota Pollution Control Agency's PFAS page or read about Minnesota's PFAS Blueprint.

Drinking Water Protection

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Environmental Health Division