In October 2019, on the recommendation of the Michigan PFAS Action Response Team (MPART), the Michigan Department of Environment, Great Lakes, and Energy (EGLE) provided draft rules to Governor Whitmer. The purpose of these rules is to establish maximum contaminant levels (MCLs) for seven PFAS compounds in approximately 2,700 water supplies in Michigan.

An MCL is the maximum amount of a contaminant allowed in drinking water[1]. MCLs are set through a scientific process that evaluates contaminants for their potential to harm human health. When the amount of a contaminant in drinking water is higher than the MCL, the water supply must take action such as treatment or follow-up testing.

Proposed PFAS MCLs


MCL (ng/L)

Chemical Abstract Services Registry Number (CASRN)

Perfluorononanoic Acid (PFNA)



Perfluorooctanoic Acid (PFOA)



Perfluorooctane Sulfonic Acid (PFOS)



Perfluorohexane Sulfonic Acid (PFHxS)



Hexafluoropropylene Oxide Dimer Acid (HFPO-DA)
(a GenX compound)



Perfluorobutane Sulfonic Acid (PFBS)



Perfluorohexanoic Acid (PFHxA)




These proposed MCLs were set based on health-based values (HBVs) established by the MPART Science Advisory Work Group. The HBVs were set at amounts that pose little to no health risk for those that drink the water over their lifetime.[2] HBVs are not enforceable. The SAWG included water quality, research and public health scientists. The SAWG evaluated existing and proposed standards nationwide for the PFAS included in USEPA Method 537.1, including those above.

PFAS Rulemaking

In November 2019, the Michigan Environmental Rules Review Committee (ERRC) voted to move forward with formal rulemaking.

The official public comment period was open between December 2019 and January 2020.  Public hearings took place on January 8, 14, and 16, 2020, during which public comments were received. During the public comment period, over 3,300 written comments were received, logged, and reviewed by EGLE Drinking Water and Environmental Health Division staff.

A summary of public comments was prepared and provided to the ERRC ahead of their February meeting, along with updated draft rule language.  The ERRC voted to approve the rules as submitted at that meeting. The rules will now be provided to the Michigan Office of Administrative Hearings and Rules to be prepared for submission to the Joint Committee on Administrative Rules (JCAR).

A recording of the February 27, 2020 ERRC meeting can be found on the ERRC webpage. A copy of the meeting packet-- including draft rules, a summary of the public comments, copies of those comments, transcripts of all three public hearings, and other supporting documents--is available on the ERRC Meeting Packet webpage.

Learn more information on this and any additional drinking water rule promulgation efforts by EGLE.

A copy of the draft rules can also be found on the Department of Licensing and Regulatory Affairs Administrative Rulemaking System web page, along with the regulatory impact statement and cost benefit analysis, and other updated information related to the rulemaking process.