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MDHHS Comparison Values

MDHHS Comparison Values

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State and federal drinking water regulatory and health-based values (or numbers) are put in place to help protect your health. While both sets of values are important for reducing your exposure to PFAS, there are distinct differences between the two. Additionally, it is important to note these values are only set for drinking water PFAS levels.

  • Regulatory Values for Public Water Systems

    Regulatory values for PFAS are called maximum contaminant levels (MCLs) and they are the highest level of PFAS that can be allowed in drinking water distributed by public water supplies. MCLs are enforceable, meaning public water suppliers are required to keep PFAS levels below MCLs to avoid penalties.

    If you are on a public water supply (for example, if you pay a water bill), you are protected by the Michigan Safe Drinking Water Act (SDWA). SDWA allows the Michigan Department of Environmental, Great Lakes, and Energy (EGLE) to set regulatory standards for drinking water contaminants, including some PFAS.

    See the chart in the “MCLs and Health-Based Values” section for the actual MCLs enforced in Michigan.

  • Health-Based Values

    The State of Michigan developed health-based values for drinking water. These values are not enforceable but rather serve as a guide. You may also see these called comparison values.

    See the chart in the “MCLs and Health-Based Values” section for the actual health-based values recommended for private residential well owners in Michigan.

  • MCLs and Health-Based Values

    PFAS Analyte (type) MCL (for public water supplies) HBV (for private residential wells)
    PFOS 16 ppt 8 ppt
    PFOA 8 ppt 8 ppt
    PFNA 6 ppt 6 ppt
    PFHxS 51 ppt 51 ppt
    PFBS 420 ppt 420 ppt
    PFHxA 400,000 ppt 400,000 ppt
    GenX 370 ppt 370 ppt

  • Additional Reading about MCLs, HBVs and drinking water

    For a more in-depth look at these values, check out the following resources.

    Michigan's Screening Values & MCLs - Per- and Polyfluoroalkyl Substances (PFAS)
    This document lays out the various values the State of Michigan is using to ensure that we are all drinking the safest water possible.

    Quick Guide to Michigan’s Screening Levels and MCLs for PFAS
    This document provides a high-level overview of the timeline and background of Michigan’s public health screening values and development of the Maximum Contaminant Levels (MCLs).

    Understanding the Risk: What’s Behind the Numbers (PFAS)
    This document breaks down and explains all the considerations that go into the development of public health screening levels and regulatory criteria. In addition, there are graphics that show state and federal values and their considerations for each.

    MDHHS Public health drinking water screening levels for PFAS
    This document gives an in-depth look into the process that MDHHS employed to develop the public health drinking water screening levels for several PFAS.

    Care for MI Drinking Water
    Tap into the facts to learn how you can maintain your home's drinking water quality and protect your health.

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