Details on the EPA Proposed MCL for PFAS in Drinking Water

Details on the EPA Proposed MCL for PFAS in Drinking Water image
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Per-and polyfluoroalkyl substances (PFAS) are facing increasing regulations, and the most recent proposal would limit concentrations in drinking and/or groundwater.

In March 2023, the Environmental Protection Agency (EPA) published a proposal to create a National Primary Drinking Water Regulation (NPDWR) to limit specific PFAS compounds in drinking water. The latest in a growing list of proposed PFAS regulations, these drinking water standards would limit the Maximum Containment Level (MCL) to an enforceable concentration of four parts per trillion (ppt) for two PFAS compounds—the lowest concentration that laboratories can reliably measure to demonstrate compliance. However, the proposed maximum containment level goal (MCLG) for the EPA is zero part per trillion.

The two compounds—perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS)—are presumed to have a higher human health risk at even the smallest levels. The proposed 4/ppt MCL for these compounds would be lower than any enforceable limits set by any state thus far.

Other PFAS chemicals impacted by the proposal are perfluorohexane sulfonate (PFHxS), hexafluoropropylene oxide dimer acid and its ammonium salt (GenX chemicals), perfluorononanoic acid (PFNA), and perfluorobutanoic acid (PFBS). For these four compounds, the EPA proposes an approach currently used in some states—the Hazard Index—to determine whether the combined levels of those PFAS chemicals in drinking water pose a risk to human health.

Once enacted, the NPDWR would require public water systems to monitor for these PFAS chemicals and notify the public of their levels. If the MCL exceeded the proposed enforceable level of 4 ppt, municipalities would be required to reduce PFAS levels through various available methods, such as adsorption onto granular activated carbon (GAC) or membrane filtration systems.

Municipalities and other affected potable water utility systems are encouraged to begin planning their approach to mitigate PFAS in drinking water. While public drinking water systems will have three years after finalization to come into compliance, some entities may find themselves facing significant financial and legal requirements.

What to Expect from MCL Regulations

One of the biggest challenges some municipalities may face with NPDWR restrictions is the unknown financial burden to comply with expected regulatory action, and how that may be passed down to the public. There may be significant costs associated with the administration, monitoring, and lengthy treatment of PFAS as entities adjust to new regulations.

If water systems are required to dispose of their PFAS remediation treatment’s spent granular carbon or resin membranes as hazardous waste, the EPA estimates that total utilities’ aggregate annual costs would increase by $30-$61 million annually. Understanding that costs associated with PFAS MCL compliance will need to be amortized over decades and, without federal help, may be passed on to water users as higher potable water rates, this estimate may be inaccurate. In addition, low-income or low-tax-base communities may be disproportionally affected.

These new federal standards also may create an opportunity for states to establish PFAS MCLs for their drinking water sources, including groundwater and surface water discharge standards. Natural bodies of water (such as lakes and rivers) that have been identified as a “public drinking water supply” may receive direct discharges or stormwater discharges that may contain PFAS concentrations exceeding the proposed MCL. These potable water resources may be subject to new discharge limitations, and stormwater dischargers may be required under the National Pollutant Discharge Elimination System (NPDES) multi-sector permit to initiate a sampling protocol for PFAS.

A separate EPA proposal, also expected to be finalized later this year, would designate PFOA and PFOS chemicals as hazardous substances. If enacted, public entities would be subject to increased PFAS regulation under Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). The EPA is requesting public comments, which are open until May 30, 2023. A virtual hearing on the proposal is planned for May 4, 2023.  

The proposed designation is likely to face legal challenges by states, industry groups, and other interested parties. While the EPA intends to finalize the rule by late 2023, we may not be aware of all possible implications for a considerable amount of time. As these chemical compounds are the same two compounds facing MCL scrutiny, it seems likely further regulation will be considered as the PFAS landscape evolves and the potential for litigation increases.

PFAS Funding Opportunities

The EPA expects roughly 66,000 water systems to be affected by this ruling, with as many as 6,300 systems expected to exceed one or more MCL.

Federal funding may be available for municipalities to address PFAS in their drinking water. The Bipartisan Infrastructure Law (BIL) makes up to $9 billion available for communities impacted by PFAS and other emerging contaminants. Of this funding, $4 billion is through the Drinking Water State Revolving Fund (DWSRF) and $5 billion through the EPA’s Emerging Contaminants in Small or Disadvantaged Communities Grant Program.

States and communities may also leverage an additional $12 billion in BIL DWSRF funds allocated toward developing safer drinking water.

Determining eligibility for or accessing this funding can be challenging. It is recommended to work with a third-party environmental consultant to ensure every option is explored that could benefit your municipality.

Working with a Consultant

The EPA anticipates that, once fully implemented, the MCL regulation could prevent thousands of PFAS-related adverse effects on humans. While this is positive news, public water supply entities will bear a heavy burden on the path toward PFAS regulatory compliance.

This long-term uncertainty underscores the value of working with an experienced third-party consultant as you begin a vulnerability assessment and begin the process of establishing potential environmental liabilities and regulatory responses, as well as what risk management options may be available for you moving forward. Partnering with an agency like FirstCarbon Solutions (FCS), an ADEC Innovation, ensures your water supply—and its consumers—remain safe and compliant throughout the regulatory process.

FCS comprises more than 100 individuals offering due diligence, technical analysis, planning, environmental compliance, permitting, and mitigation/monitoring services for both public and private projects. Our technical and legal teams provide assistance and guidance in breaking down your value chain to diagnose the most effective plan of action for your individual project. Free consultations are available to discuss your current and potential future obligations and how to prepare for the response to the latest PFAS regulations.

About the author

Jorge Caspary

Jorge Caspary thumbnail

Jorge has 25 years of experience in technical and management decisions in the areas of environmental assessment and site cleanup, solid and hazardous waste management, RCRA/CERCLA program and policies, brownfields redevelopment, and contaminated property reuse strategies. Additionally, he has also consulted and provided strategic direction and technical support on complex closures of contaminated properties and as well as engaged with other states and EPA regional and headquarters regulators.

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In an ever-changing regulatory and sustainability environment, FCS understands the challenges you face. Our highly qualified environmental specialists, energy management consultants, and technical experts deliver integrated, industry-specific solutions that move your project forward—so that you can focus on what matters.