In August 2020, the Michigan Department of Environment, Great Lakes, and Energy (EGLE) promulgated rules establishing maximum contaminant levels (MCLs) for seven PFAS compounds under the authority of the Safe Drinking Water Act. These levels were based on health based values provided by the MPART Science Advisory Workgroup in its 2019 report, Health-Based Drinking Water Value Recommendations for PFAS in Michigan.
Maximum contaminant levels apply to approximately 2,700 public drinking water supplies in Michigan.
|
Specific PFAS |
Drinking water MCL (ppt) |
|---|---|
|
PFNA |
6 ppt |
|
PFOA |
8 ppt |
|
PFHxA |
400,000 ppt |
|
PFOS |
16 ppt |
|
PFHxS |
51 ppt |
|
PFBS |
420 ppt |
|
HFPO-DA |
370 ppt |
ppt = parts per trillion
A maximum contaminant level (MCL) is the maximum amount of a contaminant allowed in a public drinking water supply.
Compliance with Michigan’s MCLs for PFAS is determined based on a calculated running annual average of sample results for a public water supply. When the running annual average of a contaminant in drinking water is higher than the MCL, the water supply must take action as outlined in the Safe Drinking Water Act or its accompanying administrative rules.
Such actions may include:
Drinking water rules in Michigan were amended to include the above PFAS MCLs, establishing sampling requirements for these seven PFAS compounds in public water supplies covered under the Michigan Safe Drinking Water Act.
In April 2024, US EPA announced the final National Primary Drinking Water Regulation (NPDWR) for PFAS. US EPA established Maximum Contaminant Levels (MCLs) for six PFAS in drinking water:
as contaminants with individual MCLs, and PFAS mixtures containing at least two or more of:
using a Hazard Index MCL. US EPA also finalized health-based, non-enforceable Maximum Contaminant Level Goals (MCLGs) for these PFAS.
Public water supplies must complete initial monitoring by June 2027, with ongoing compliance monitoring and reporting required after that date. Beginning in June 2029, public water supplies that have PFAS in drinking water which exceeds one or more of the US EPA MCLs must take action to reduce PFAS levels provide notification to the public of the violation.
In May 2025, US EPA issued a press release announcing that the agency intends to keep the NPDWR for PFOA and PFOS, and indicating that they would extend the compliance date to 2031.
