PFAS Drinking Water Standards in Massachusetts
“Forever chemicals” are now formally regulated in U.S. drinking water — and Massachusetts has its own standard that’s been in force since 2020. Here’s a plain-English look at where the federal EPA rule and MassDEP’s PFAS6 standard stand as of mid-2026, and what it means whether you’re on public water or a private well.
What PFAS Are & Why They Matter
PFAS (per- and polyfluoroalkyl substances) are a family of thousands of man-made chemicals used since the 1940s in nonstick cookware, stain- and water-resistant fabrics, food packaging, and firefighting foam. They’re nicknamed “forever chemicals” because their carbon-fluorine bonds resist breaking down — they persist in soil, water, and the human body for years. EPA has linked long-term PFAS exposure to health effects including certain cancers, thyroid disruption, immune suppression, elevated cholesterol, and developmental effects during pregnancy.
PFAS contamination isn’t limited to sites near factories or military bases. Because these chemicals were used so widely — and because firefighting foam and biosolids spread them further — many Massachusetts public water systems and private wells have measurable PFAS, particularly in communities near airports, fire-training areas, and older industrial sites.
The Federal EPA Rule
In April 2024, the EPA finalized its first-ever National Primary Drinking Water Regulation for PFAS, setting enforceable Maximum Contaminant Levels (MCLs) for public water systems:
- PFOA and PFOS: 4 parts per trillion (ppt) each, individually — among the strictest drinking-water limits EPA has ever set.
- PFHxS, PFNA, and HFPO-DA (GenX chemicals): 10 ppt each.
- Hazard Index: a combined-mixture calculation covering PFHxS, PFNA, HFPO-DA, and PFBS together, meant to catch cumulative risk even when no single chemical exceeds its own limit.
Public water systems must monitor for these compounds, notify customers of results, and reduce levels that exceed the limits. The original compliance deadline was 2029.
2025–2026 status: The rule has been in motion. In May 2026, EPA proposed two changes: (1) extend the compliance deadline for the PFOA and PFOS MCLs from 2029 to 2031, and (2) rescind the MCLs and Hazard Index requirement for PFHxS, PFNA, and HFPO-DA/GenX, citing procedural concerns with how those specific limits were originally adopted. EPA has stated it intends to keep the 4 ppt enforceable limits for PFOA and PFOS, and has said it will reconsider standards for the other compounds through a proper rulemaking process — which could ultimately result in equally strict or stricter limits. A public comment period and hearing were underway in July 2026, with final action still pending. Because this is actively changing, confirm the current status directly at epa.gov/sdwa before treating any specific number as final.
Massachusetts’ PFAS6 Standard (MassDEP)
Massachusetts didn’t wait for the federal government. Since October 2020, MassDEP has enforced its own Massachusetts Maximum Contaminant Level (MMCL) of 20 nanograms per liter (ng/L), or 20 parts per trillion, for the sum of six PFAS compounds — known as “PFAS6”: PFOS, PFOA, PFHxS, PFNA, PFHpA, and PFDA. This standard applies to community and non-transient non-community public water systems statewide.
Because MassDEP regulated PFAS years ahead of the federal government, many Massachusetts water suppliers have already been testing and, where needed, installing treatment since 2020–2021. EPA has granted MassDEP an extension (through April 2028) to align its state program with the newer federal framework, which means the PFAS6 standard remains Massachusetts’ operative drinking-water rule for public systems while the federal rule continues to evolve.
If you’re on a public water supply
Your utility is already required to test for PFAS6 and, under the evolving federal rule, for PFOA/PFOS and related compounds. Results are reported in your water system’s annual Consumer Confidence Report (CCR) — ask your town’s water department for the latest one, or look it up online. If your supply exceeds the state or federal limit, the utility must notify customers and take corrective action.
If you have a private well
Neither the MassDEP PFAS6 standard nor the EPA rule applies to private wells — testing is voluntary and the responsibility falls on the homeowner. MassDEP recommends private well testing, especially for homes near airports, fire-training sites, or known contamination areas. If PFAS is detected, point-of-use or point-of-entry treatment (activated carbon, reverse osmosis, or ion exchange) is the primary way to protect your household.
Frequently Asked Questions
What are the current PFAS drinking water limits in Massachusetts?
Public water systems in Massachusetts must meet MassDEP’s PFAS6 standard of 20 ppt for the combined sum of six PFAS compounds. The federal EPA rule additionally sets a 4 ppt individual limit for PFOA and PFOS, with limits for other PFAS currently under EPA reconsideration as of mid-2026. Because both standards are evolving, always confirm the current numbers with EPA or MassDEP.
Do these rules apply to my private well?
No. Both the MassDEP PFAS6 standard and the EPA rule apply only to public water systems. Private well owners aren’t required to test, but MassDEP strongly recommends it — particularly near known risk areas — since well water isn’t monitored by anyone but you.
How do I find out if my water has PFAS above the limit?
If you’re on public water, check your utility’s Consumer Confidence Report or call your water department. If you’re on a private well, the only way to know is to test it. We offer a free water test for Massachusetts homeowners to find out exactly what’s in your water and what, if anything, needs treatment.
Not Sure What’s in Your Water?
We’ll test your water, explain exactly what we find in plain English, and walk you through whether treatment makes sense for your home — no pressure, no jargon.