PFAS: EPA and NYSDEC Regulatory Updates

by | Apr 4, 2023

EPA Proposed PFAS National Drinking Water Regulation

On March 14, 2023, the Environmental Protection Agency (EPA) proposed a National Primary Drinking Water Regulation (NPDWR) to establish Maximum Contaminant Levels (MCLs) for six per- and polyfluoroalkyl substances (PFAS). Once finalized, these will be the first-ever national drinking water standards for PFAS.

The most common PFAS species, perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), would be regulated as individual contaminants. The other four PFAS species would be regulated as a mixture and these include perfluorononanoic acid (PFNA), hexafluoropropylene oxide dimer acid (HFPO-DA, commonly known as GenX Chemicals), perfluorohexane sulfonic acid (PFHxS), and perfluorobutane sulfonic acid (PFBS).

Along with the proposed MCLs, the EPA has proposed Maximum Contaminant Level Goals (MCLGs) that are health-based and non-enforceable, but provide the maximum level of a contaminant in drinking water where there are no known or anticipated negative health effects. The MCLs and MCLGs are listed in the table below.

Compound Proposed MCLG Proposed MCL (enforceable levels)
PFOA Zero 4.0 parts per trillion
PFOS Zero 4.0 parts per trillion

1.0 (unitless)


Hazard Index

1.0 (unitless)


Hazard Index


The proposed NPDWR builds upon actions being taken by the EPA to address PFAS to safeguard public health, protect the environment, and hold polluters accountable. Addressing PFAS contamination will be a challenge many water purveyors will have to navigate. If levels are detected above EPA limits, costly treatment systems will need to be installed. Federal and state funding opportunities will be available to help address this issue.


NYSDEC Releases Final Ambient Water Quality Guidance Values for PFOA, PFOS, and 1,4-Dioxane

On March 15, 2023, the New York State Department of Environmental Conservation (NYSDEC) issued final water quality guidance values for PFOA, PFOS, and 1,4-Dioxane in New York State waters.

Chemical Final Ambient Water Quality Guidance Values
Human Health Aquatic Life
Chronic Acute
PFOA 6.7 ppt N/A N/A
PFOS 2.7 ppt

160 ppb (fresh)

41 ppb (saline)

710 ppb (fresh)

190 ppb (saline)

1,4-Dioxane 0.35 ppb

18,000 ppb (fresh)

7,000 ppb (saline)

160,000 ppb (fresh)

63,000 ppb (saline)

These guidance values (GVs) strive to protect ambient waters that are used as drinking water sources. Facilities with industrial wastewater discharges will see these GVs incorporated into their SPDES permits. This action aims to reduce discharge of these contaminants into the environment. By addressing contamination at the source, downstream treatment systems will be protected.

Please reach out to Walden at 516-271-1948 if you need assistance determining how these regulatory changes could impact your operations. Walden continues to follow regulatory developments on emerging contaminants and strives to help our clients to be proactive in addressing potential compliance issues.

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Visit some of Walden’s other pages to learn about our drinking water services and read other blogs about PFAS. Contact us at 516-271-1948 to speak with an experienced staff member!