On July 27, the Michigan Legislature’s Joint Committee on Administrative Rules (JCAR) filed new administrative rules and rule amendments concerning Michigan’s drinking water standards with the Michigan Secretary of State’s office. Included among the new rules are maximum contaminant levels (MCLs) for seven different types of per- and polyfluoroalkyl substances (PFAS). All of the new rules and rule amendments will take effect on August 3, 2020.

The new PFAS MCLs establish enforceable limits on PFAS in drinking water that will be applied to public drinking water supplies as well as groundwater cleanups throughout the state as cleanup criteria. Currently, the state groundwater cleanup criteria for PFAS is 70 parts per trillion (ppt or ng/l) for PFOA and PFOS in any combination, which are two of the most well-researched PFAS types. The new Michigan Administrative Rule 325.10604g, however, sets new PFAS limits as follows:

Contaminant Maximum Contaminant
Level in ng/l
Hexafluoropropylene oxide dimer acid (HFPO-DA) 370
Perfluorobutane sulfonic acid (PFBS) 420
Perfluorohexane sulfonic acid (PFHxS) 51
Perfluorohexanoic acid (PFHxA) 400,000
Perfluorononanoic acid (PFNA) 6
Perfluorooctane sulfonic acid (PFOS) 16
Perfluorooctanoic acid (PFOA) 8

The rule states that the MCLs apply to “community” and “nontransient noncommunity” water supplies (definitions included below), and that compliance with these MCLs will be “determined based on the analytical results obtained at each sampling point. If 1 sampling point is in violation of an MCL, then the supply is in violation of the MCL.” The rule goes on to state how sampling data should be calculated to determine compliance with the MCLs for applicable public water supplies. In turn, new Rule 325.10717d specifies standards for collection and analysis of water samples from public water supplies for PFAS.

Notably, however, Rule 325.10717d also appears to expand the reach of the PFAS MCLs to all public water supplies — not just the “community” and “nontransient noncommunity” types. Subsection (2) of the rule states that “the department may require samples to be collected and analyzed at prescribed frequencies for per- and polyfluoroalkyl substances” for the remaining two public water supply types, known as “transient noncommunity” and “Type III” public water supplies. The rule then goes on to prescribe standards that appear to depend on the concentration of PFAS in a given sample and not on the type of public water supply the sample came from — for example, subsection (10) of the rule requires additional monitoring if any sample exceeds the PFAS MCLs, and subsection (14) states that “[a]ll new supplies or supplies that use a new source of water shall demonstrate compliance with the MCLs before serving water to the public.” Through these and other provisions of the rule, it appears that “transient noncommunity” and “Type III” public water suppliers can be made to comply with the PFAS MCLs.[i]

Along with the MCLs, however, Rule 325.10308b, titled “Best available technology,” specifies that granular activated carbon (GAC) or “an equally efficient technology” are the best available technologies for the treatment of the PFAS types listed in the table above. The inclusion of the phrase “or an equally efficient technology” is likely intended to (1) capture any new treatment technologies that may present themselves in the near future, due to the rapidly evolving research around PFAS; and (2) provide flexibility to water suppliers in their choice of additional treatment technologies that are currently available and have shown the potential to provide “equally efficient” treatment of PFAS, such as certain types of anion exchange filtration systems. Further, although this rule is intended to apply to public water supply treatment, it may indicate the acceptance of “equally efficient” treatment technologies for groundwater cleanups, as well.

Finally, Rule 325.10401a specifies the public notice procedures required for applicable public water systems to report certain rule violations and exceedances, including exceedances of the new PFAS MCLs. Rules 325.12701, 12708, and 12710 discuss laboratory certification requirements for those labs testing for PFAS in water samples.

Practical Considerations for Groundwater Cleanups

The practical effects of these new MCLs are certainly far-reaching for both public water systems and groundwater cleanups. However, the effect on groundwater cleanups is likely to be especially pronounced. As of August 3, cleanups across the state will have to rapidly adjust to severely reduced PFOA and PFOS cleanup targets — and they will also have to account for five new PFAS types that were previously not in focus. This may result in additional testing and shifting regulatory goals at established cleanup sites, even for those cleanups that are currently underway pursuant to established administrative orders, due in part to the reopener provisions that are typically included in those agreements.

Beyond the effects on established cleanup sites, however, the MCLs are also going to bring new sites into EGLE’s focus. The agency recently announced that the new MCLs are going to result in 42 new sites being added into the Michigan PFAS Action Response Team (MPART) portfolio. Per EGLE:

Half of the new sites are landfills and more than a dozen are former plating or manufacturing sites. Many sites are also the subject of ongoing EGLE investigations into other forms of contamination. Summaries of the new sites will be posted on the MPART web site after the rules become official. Additionally, MPART will schedule a series of regional webinars to provide more information regarding next steps in the state’s investigation into PFAS contamination at these sites.

The attorneys at Troutman Pepper are actively working to assist companies in evaluating these complex issues and working with environmental regulators during this challenging time. For more information on these issues, please contact the authors.

[i] For reference, a “community water supply” is defined as “a public water supply that provides year-round service to not fewer than 15 living units or that regularly provides year-round service to not fewer than 25 residents”; a “noncommunity water supply” is defined as “a public water supply that is not a community supply, but that has not fewer than 15 service connections or that serves not fewer than 25 individuals on an average daily basis for not less than 60 days per year”; a “nontransient noncommunity water supply” is defined as “a noncommunity public water supply that serves not fewer than 25 of the same individuals on an average daily basis over 6 months per year. This definition includes water supplies in places of employment, schools, and day-care centers”; a “transient noncommunity water supply” is  defined as “a noncommunity supply that does not meet the definition of nontransient noncommunity water supply”; and a “Type III” public water supply is any public water supply that (1) is not considered to be any type of community or noncommunity water supply, and (2) does not supply water to only one living unit.