We're kicking off this initiative with the fact that surprised us most once we started digging: Marshfield's own combined PFAS6 testing — the state's headline measure, covering six compounds together — came back at ND to 13.0 parts per trillion in 2023, comfortably under Massachusetts' 20 ppt standard. By that yardstick, this is a genuinely clean, well-run groundwater system, entirely local, drawing from sixteen wells across six aquifers with no purchased water anywhere in the mix.
But a narrower, compound-specific look complicates that picture. The Furnace Brook #1A well was reported testing at 4.85 parts per trillion for PFOA alone in July 2024 — above the newer federal individual limit of 4 ppt, even though it's nowhere near the state's combined 20 ppt threshold. Regional reporting citing water-system data indicates two other Marshfield wells test similarly, putting three of seven actively-tested wells above the federal PFOA limit. Marshfield's own Consumer Confidence Report doesn't break results out well-by-well, so we can't confirm or refute the full extent of this from the town's own published document alone — which is itself worth knowing. Two numbers, both real, both from the same town's wells, telling two different stories depending on which standard you're measuring against.
There's a third layer, too: Marshfield's own report describes its Duxbury connection as "emergency...if needed," while Duxbury's own reporting describes an ongoing, billed, ~150-home supply arrangement to the Gurnet Road neighborhood. We don't think either town is lying — we think it's a real example of two water systems describing the same pipe differently in their own paperwork. See the full breakdown, including exactly what we could and couldn't independently verify, on our Water data page.
Long before there was a federal PFAS rule, there was a Massachusetts one. In October 2020, MassDEP finalized an enforceable drinking water standard — a Maximum Contaminant Level, or MCL — of 20 parts per trillion for the combined total of six PFAS compounds, a grouping the state calls "PFAS6": PFOS, PFOA, PFHxS, PFNA, PFHpA, and PFDA.
At the time, this made Massachusetts one of a small number of states with any enforceable PFAS standard at all. For the Marshfield DPW Water Division, this is the exact standard its combined PFAS6 results have consistently tested under — ND to 13.0 ppt as of the town's 2023 report — a genuinely clean result by the state's own combined yardstick, even as the newer federal individual-compound limit tells a more complicated story for at least one well.
Source: Mass.gov — Massachusetts PFAS Drinking Water Standard (MCL).
Until April 2024, there was no federal limit on PFAS in drinking water at all — only the Massachusetts state standard set in 2020. That changed when EPA finalized its National Primary Drinking Water Regulation (NPDWR) for PFAS: the first time PFAS compounds have been individually, enforceably regulated at the federal level.
The rule set limits of 4 parts per trillion (ppt) each for PFOA and PFOS, 10 ppt each for three additional compounds (PFHxS, PFNA, and HFPO-DA), and a combined "Hazard Index" limit for mixtures of those plus PFBS. Water systems nationwide were given until 2027 to complete initial monitoring and until 2029 to come into full compliance.
For Marshfield, this is the exact rule that the Furnace Brook #1A well's 4.85 ppt PFOA reading (July 2024) exceeds — a reading that arrived the same month this federal rule's individual limits took legal shape, even though Marshfield's own combined system-wide PFAS6 number stays well under the separate state threshold.
Source: Federal Register — PFAS National Primary Drinking Water Regulation.
We're not going to soften this and we're not going to overstate it either: Marshfield's combined, system-wide PFAS6 result is genuinely clean — ND to 13.0 ppt in the town's 2023 reporting, well under Massachusetts' 20 ppt standard, with no violation on record. If you only look at that number, this is a well-run system with nothing to flag.
But that's not the whole picture. The Furnace Brook #1A well was reported testing above the federal 4 ppt individual PFOA limit (4.85 ppt, July 2024), and regional reporting citing water-system data puts three of Marshfield's seven actively-tested wells above that same federal threshold. Marshfield's own published Consumer Confidence Report doesn't break PFAS results out well-by-well, which means residents can't currently check which specific well serves their address against these numbers using the town's own official document alone — a real gap in public reporting, not something we're speculating into existence.
See the full compound-by-compound breakdown, including what we can and can't confirm, on our Water data page.
On May 18, 2026, EPA announced two proposals that affect the federal PFAS rule described above. The first (Docket EPA-HQ-OW-2025-1742) would let water systems request a two-year extension — from 2029 to 2031 — to comply with the enforceable limits for PFOA and PFOS, while requiring systems measuring 12 ppt or higher to take short-term mitigation action during the extension. The second (Docket EPA-HQ-OW-2025-0654) would rescind the individual limits for three other PFAS compounds (PFHxS, PFNA, and HFPO-DA/GenX) and the combined "Hazard Index" limit for mixtures of those plus PFBS, on the grounds that EPA says the prior process didn't follow required Safe Drinking Water Act procedure.
What doesn't change: the 4 ppt limits for PFOA and PFOS individually are not part of either rescission proposal. For Marshfield, where at least one well already tests above that specific 4 ppt PFOA line, the compliance-extension proposal is the one worth watching — the rescission proposal targets different compounds entirely.
EPA held a virtual public hearing on July 7, 2026. As of today — July 21, 2026 — the comment dockets closed yesterday, July 20, 2026, with more than 15,000 comments submitted. Nothing here is final yet; treat the 2024 rule as the current baseline until EPA actually finalizes a change, and check back here as the rulemaking moves toward a decision later this year.
See the full regulatory timeline for how this fits with the 2020 state standard and the 2024 federal rule.
System-wide data only tells part of the story — which well serves your street and how long water sits in your pipes can all change what actually comes out of your tap.
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