EPA Finalizes Water MCLs for Public Water Systems

After years of study, the Environmental Protection Agency (EPA) has finalized the National Primary Drinking Water Regulation (NPDWR) to control six toxic PFAS compounds in Public Water Systems. The EPA believes that between 6% to 10% of the 66,000 public drinking water systems subject to this regulation will need to reduce PFAS to satisfy the new maximum contaminant levels (MCLs). This highly anticipated regulation represents a major step in minimizing exposure to these persistent “forever chemicals” that have contaminated drinking water sources nationwide.

New Limits Set for Six PFAS Compounds

The new rule sets enforceable MCLs for six specific per- and polyfluoroalkyl substances (PFAS):

PFOA and PFOS: 4 parts per trillion (ppt) The lowest allowable level ever set for a drinking water contaminant.
PFNA, PFHxS, GenX (HFPO-DA): 10 ppt each
Mixtures containing two or more of PFHxS, PFNA, HFPO-DA, and PFBS: Hazard Index of 1.0 (The sum of ratios cannot exceed 1).

Recognizing that PFAS are highly mobile and persist indefinitely in the environment, the EPA aims to virtually eliminate these toxic chemicals from drinking water sources by driving levels as close as feasible to zero. Stringent standards are backed by substantial evidence linking PFAS exposure to increased risk of cancers, developmental issues, thyroid disease, compromised immune function, and other serious adverse health effects.

Understanding MCLs and MCLGs

Maximum Contaminant Level Goals (MCLGs) and Maximum Contaminant Levels (MCLs) while closely related, serve different purposes in the management of drinking water safety.

Maximum Contaminant Level Goals (MCLGs): MCLGs are non-enforceable public health objectives. Essentially, they represent ideal conditions, setting the contaminant levels in drinking water at points where no known or anticipated adverse health effects occur, with an added margin of safety. MCLGs are aspirational, aiming to guide the protection of human health without considering the practical limitations of current detection and treatment technologies. Therefore, MCLGs can sometimes be set at levels that are not currently achievable by water treatment systems, as they do not take into account the technological feasibility or cost of removal.
Maximum Contaminant Levels (MCLs): In contrast, MCLs are enforceable standards under the Safe Drinking Water Act. These are the legal thresholds that define the maximum permissible concentration of a contaminant in the water provided by public water systems. MCLs are set as close to the MCLGs as possible, taking into account both the capability of available treatment technologies and the cost-effectiveness of achieving these levels. MCLs ensure that water systems strive to meet the safest practical standards for drinking water quality.

PFAS-MCLs-Limits

PFAS MCLs Compliance Timeline

To quickly achieve the public health benefits, the EPA has set an aggressive schedule for public water systems to implement the new standards:

June 25, 2024: The final rule goes into effect.
April 26, 2027: Complete initial PFAS monitoring to establish baseline levels
April 26, 2029: Comply with new enforceable MCLs

With just 5 years until the MCLs compliance deadline, entities must now:

Conduct comprehensive PFAS monitoring and reporting
Evaluate and implement approved treatment methods
Ensure consistent compliance with new maximum contaminant levels
Notify the public of monitoring and reporting and any MCL violations

Monitoring and Compliance for PFAS MCLs

To safeguard public health, the EPA has laid out specific monitoring requirements.

Groundwater systems serving more than 10,000 people will need to test their water for PFAS four times a year.
Groundwater systems serving 10,000 or fewer will conduct testing twice a year.
Surface water systems must conduct quarterly monitoring within a 12-month timeframe.

Action Steps Post-Monitoring

Any public water system that discovers PFAS levels exceeding the set limits must inform the community they serve and implement strategies to reduce PFAS concentrations. The EPA did not specify strategies for PFAS reduction, allowing flexibility in choosing the most suitable method. However, recommended technologies include granular activated carbon (GAC), anion exchange (AIX), nanofiltration (NF), and reverse osmosis (RO).

PFAS MCLs State-Level Compliance

With the establishment of MCLs for six PFAS compounds, all states must now comply with these federal standards under the Safe Drinking Water Act (SDWA). States have the option to either adopt these new federal standards or develop their own, provided they as strict or stricter. This ensures uniform protection across the nation, regardless of individual state policies.

Learn more about the final rule here.

Final Thoughts

The new PFAS regulation set by the EPA marks a significant advancement to safeguard public health from the pervasive threats of ‘forever chemicals’. These standards are not just about achieving compliance; they are about protecting the quality of our water resources for generations to come.

With rigorous monitoring requirements and stringent contaminant levels to meet, the road ahead requires robust planning and precise implementation.

AEI’s deep expertise equips us to guide you effectively through the complexities of this new regulatory environment. Our capabilities include but are not limited to:

Assessment of PFAS risks through our Phase I ESA Environmental Site Assessment process
PFAS Sampling through our Phase II Environmental Site Assessments
Monitoring and Reporting
Regulatory advocacy
Remedial investigations
Feasibility studies
Risk assessments
Remedial design
Remedial implementation
Operation and management

Whether your system is just starting to evaluate its PFAS vulnerability, or you need assistance optimizing an existing treatment process, our team of professionals can deliver tailored solutions to achieve compliance.

Don’t leave your system exposed to risk, hefty fines, or public safety violations. Contact AEI to develop and execute a comprehensive PFAS strategy for your public water system.

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