Most people who've lived in Hanover for a while already know the basics: sometimes the water runs a little cloudy or rust-tinted, especially after a hydrant flush or main break. That's not a mystery or a cover-up — it's naturally occurring iron and manganese in the town's groundwater, and it's the entire reason Hanover built and operates three separate treatment plants: Beal (1994), Pond Street (1973, upgraded 1992), and Broadway (2001). Together they treat roughly 500 million gallons a year, using processes ranging from manganese-greensand filtration to conventional chemical treatment and sedimentation.
What's newer is that those same three plants are now doing double duty. Pond Street's PFAS6 exceedances in 2021 and 2023 pushed the town to add GAC filtration there, and a 2025–26 pilot study testing GAC against ion-exchange resin found both could bring PFOA and PFOS below 2 parts per trillion — well under the federal government's eventual 4 ppt limit. In May 2026, Hanover voters approved $32 million to upgrade PFAS treatment at all three plants, on top of the mineral-removal infrastructure that's been running for decades. That's the most significant water infrastructure investment the town has made in recent memory, and it's why we're launching this site now: to track what that money buys, and whether it delivers.
See the full breakdown of Hanover's three plants and PFAS record on the Water data page.
On May 18, 2026, EPA announced two proposals affecting the federal PFAS rule finalized in April 2024. The first would let water systems request a two-year extension — from 2029 to 2031 — to comply with the enforceable limits for PFOA and PFOS. The second 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 rule wasn't finalized under the correct Safe Drinking Water Act procedure.
What doesn't change: the 4 ppt limits for PFOA and PFOS individually — the two compounds most consistently linked to health effects in research, and the ones Hanover's Pond Street plant has specifically had to treat for — are not part of either rescission proposal. And unlike many towns weighing whether to wait out a possible extension, Hanover has already committed $32 million to treatment upgrades that its own pilot testing shows would meet the 4 ppt PFOA/PFOS limit regardless of whether the 2029 or a 2031 deadline ends up applying.
Both proposals were still open for public comment as of this writing, with a virtual public hearing held July 7, 2026 and the comment period scheduled to close July 20, 2026. Nothing here is final; treat the 2024 rule as the current baseline until EPA actually finalizes a change.
See the full regulatory timeline for how this fits with the 2020 state standard and the 2024 federal rule.
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 Hanover specifically, the practical impact shows up at Pond Street: the plant's PFAS6 exceedances in 2021 and 2023 were measured against the older, less strict 20 ppt combined state standard. The new federal rule asks a tougher question — not just "is the combined total under 20?" but "is PFOA, on its own, under 4?" Hanover's own 2025–26 pilot study suggests its planned treatment upgrades will clear that bar with room to spare, bringing PFOA and PFOS below 2 ppt.
Source: Federal Register — PFAS National Primary Drinking Water Regulation.
Here's where things actually stand, without the spin either direction: Hanover's Pond Street treatment plant exceeded the Massachusetts PFAS6 standard (20 ppt combined) in 2021 and again in 2023. The Beal and Broadway plants have not exceeded that standard. As of the town's most recent public reporting, the system as a whole is meeting the 20 ppt state standard, following GAC media installed at Pond Street in 2022 and replaced in 2023.
That's a genuinely mixed record — not a clean bill of health with no history, and not an ongoing crisis either. What distinguishes Hanover from towns that are simply waiting out the clock on PFAS is the town's own decision to move early: all three Pond Street filters were converted to GAC media between October 2021 and September 2022, a $1.75 million design appropriation followed in 2024, a GAC-vs-ion-exchange pilot study ran July 2025–January 2026, and voters approved a $32 million bond in May 2026 to upgrade treatment at all three plants ahead of the federal government's stricter 4 ppt PFOA/PFOS limit. We'll keep tracking the results as that money gets spent.
Source: Hanover Water Department PFAS public notices (2021, 2023); see the full Water data page for the complete picture, including the violation-history caveat about EPA ECHO access.
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. The federal government wouldn't set its own limits for another three and a half years. That gap mattered directly for Hanover: it's the standard that governed the town's Pond Street plant when PFAS6 levels came in above the limit in 2021 and 2023, and it's the standard the Hanover Water Department is required to meet today.
This 20 ppt combined standard remains the operative Massachusetts rule, and it's separate from (and less strict, compound-for-compound, than) the individual federal PFOA/PFOS limit of 4 ppt that followed in 2024. Both apply simultaneously — a system has to meet whichever is more protective for a given compound, which is exactly why Hanover's treatment upgrades are being designed around the tougher 4 ppt number rather than just the 20 ppt one.
Source: Mass.gov — Massachusetts PFAS Drinking Water Standard (MCL).
System-wide data only tells part of the story — service lines, home plumbing, and private wells can all change what actually comes out of your tap.
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