Agency for Toxic Substances and Disease Registry

Understanding PFAS Levels in Tap Water

There are currently more than 4,700 different PFAS compounds, and the number is ever-growing. However, not all PFAS are well-researched or understood, and only a few have been studied extensively enough to draw conclusions about their safety. 

Two of the most well-known and researched PFAS compounds, PFOA (perfluorooctanoic acid) and PFOS (perfluorooctanesulfonic acid), have been voluntarily phased out by manufacturers in the US, but they are still present in the environment and consequently in our water supplies due to their persistent nature.

Still, PFAS persist and we are finding out the impact of the spread. In a recent study, around 70% of surface water samples where firefighting foam was known to contaminate the groundwater exceeded the proposed US Environmental Protection Agency’s hazard index with 60–80% of samples exceeding the EPA’s new drinking water regulations for perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA).

The EPA Steps In – National Primary Drinking Water Regulation

Acknowledging the widespread impact of PFAS contamination, the EPA has stepped up its efforts to regulate these chemicals. In 2020, the agency proposed the first-ever PFAS regulatory determinations under the Safe Drinking Water Act (SDWA). This move signifies the EPA’s commitment to addressing the emerging threat posed by PFAS in drinking water.

On April 10, 2024, the EPA announced the final National Primary Drinking Water Regulation (NPDWR) for six PFAS.

New PFAS Tap Water Regulations

The main goal of the new regulations is to limit the concentration of PFAS in drinking water to levels that are safe for human consumption.

To achieve this, the EPA is taking a multi-pronged approach:

1. Setting Maximum Contaminant Levels (MCLs)

One of the key strategies is establishing Maximum Contaminant Levels (MCLs), which are standards set for the acceptable concentration of specific contaminants in public water systems. 

The EPA finalized a National Primary Drinking Water Regulation (NPDWR) establishing legally enforceable Maximum Contaminant Levels for six PFAS in drinking water. PFOA, PFOS, PFHxS, PFNA, and HFPO-DA as contaminants with individual MCLs, and PFAS mixtures containing at least two or more of PFHxS, PFNA, HFPO-DA, and PFBS using a Hazard Index MCL to account for the combined and co-occurring levels of these PFAS in drinking water. The EPA also finalized health-based, non-enforceable Maximum Contaminant Level Goals (MCLGs) for these PFAS. 

EPA

2. Advanced Monitoring

The EPA also acknowledges the need for advanced monitoring to track and combat PFAS contamination. Public water systems will be required to monitor for PFAS, and the results could lead to further review or regulation if necessary.

3. Enhanced Reporting

Under the new regulations, there will be enhanced reporting requirements. Water systems will need to inform residents and governing bodies if PFAS levels exceed the recommended limits, thus ensuring greater transparency.

4. Clean-Up Efforts

Another important aspect of the regulations is to facilitate clean-up efforts. Identifying and mitigating PFAS sources is crucial to reducing ongoing contamination.

The Impact on Municipalities and Water Suppliers

The proposed regulations will significantly impact municipalities and water suppliers responsible for treating and providing safe drinking water to the community. Water suppliers may need to invest in new treatment technologies capable of removing PFAS from the water effectively, which could pose economic challenges, particularly for smaller systems.

NPDWR Timing

Here is the timeline for the rollout of the NPDWR. 

2027: 

• Public water systems have three years to complete initial monitoring for these PFAS followed by ongoing compliance monitoring. 
• Water systems must also provide the public with information on the levels of these PFAS in their drinking water.

2009:

• Public water systems must implement solutions that reduce these PFAS if monitoring shows that drinking water levels exceed these MCLs.
• Public water systems that have PFAS in drinking water which violates one or more of these MCLs must take action to reduce levels of these PFAS in their drinking water and must provide notification to the public of the violation.

Conclusion

The new PFAS tap water regulations proposed by the EPA mark a turning point in ensuring that our water remains a source of life, not harm. The proposed rules are just the beginning of a long-term battle against PFAS contamination. It will require continuous effort, vigilance, and advocacy from all stakeholders to safeguard our most precious resource—water. 

Whether we’re policymakers, water suppliers, or simply individuals who care about sustainable living, we all have a crucial role to play in this journey toward a PFAS-free future.