The Hanover Water Department (part of the Town's Department of Public Works) serves an estimated 14,800–15,000 residents — roughly the town's full population — entirely from local groundwater wells. There is no shared regional system here and no purchased water from a neighboring town: Hanover treats and distributes its own supply from its own wellfields.
That supply runs through three separate town-owned treatment plants, each built to solve the same underlying problem: Hanover's groundwater naturally carries high levels of dissolved iron and manganese, which cause discoloration, metallic taste, and staining if left untreated.
| Plant | Built / upgraded | Sources treated | Primary process |
|---|---|---|---|
| Beal (Riverside Drive) | 1994 | 2 deep bedrock wells | Manganese-greensand filtration + air stripping (also addresses radon) |
| Pond Street | 1973, upgraded 1992 | 3 groundwater wells | Conventional treatment: chemical addition, flocculation, sedimentation, mixed-media filtration |
| Broadway | 2001 | Hanover Street & Broadway well fields | Manganese-greensand filtration |
Together the three plants treat an estimated 500 million gallons per year. Source: Hanover, MA — Water Facilities and Treatment.
EPA's Safe Drinking Water Information System (SDWIS) and ECHO compliance database list a documented violation history for the Hanover Water Department spanning 2010–2024, across several different rule categories:
| Category | What's on record |
|---|---|
| Disinfection byproducts (TTHM) | Stage 2 D/DBP Rule exceedances, with a MassDEP Consent Order and public notice issued October 2015 after elevated trihalomethane levels; the town flushed affected water mains and implemented longer-term corrective measures |
| Total coliform | Monitoring/reporting issues on record for 2010–2011 |
| Volatile organic chemicals | Monitoring-schedule gaps for tetrachloroethylene (PCE) noted in 2014 and again in 2024 — a paperwork/monitoring-timing issue, not a reported detection above a health limit |
| Consumer Confidence Report | A reporting-deadline violation on record for 2010 |
| PFAS6 (state standard) | Exceedances at the Pond Street plant in 2021 and 2023, detailed below |
A note on how we got this: EPA's ECHO/SDWIS web interface blocked our automated tools from pulling a clean printout directly, so this summary reflects a best-effort reading of publicly available SDWIS violation data rather than a screenshot we can point you to. If you want to verify the exact dates and counts yourself, search "Hanover Water Dept" or PWSID MA4122000 directly at EPA ECHO — we'd rather flag that gap than present secondhand numbers as more precise than they are. Separately, in September 2025 MassDEP approved Hanover's certification that its system has zero lead, galvanized-requiring-replacement, or unknown-material service lines — a genuinely clean result worth noting alongside the rest of this record.
Massachusetts set an enforceable Maximum Contaminant Level (MCL) of 20 parts per trillion (ppt) for the combined total of six PFAS compounds ("PFAS6") in October 2020. Hanover's Pond Street treatment plant exceeded that standard on at least two documented occasions:
| Date | What happened |
|---|---|
| Aug–Nov 2021 | PFAS6 measured above the 20 ppt standard at Pond Street (April–June 2021 monitoring averaged 22.3 ppt); public notices issued |
| Nov 2023 | PFAS6 again measured above the 20 ppt standard at Pond Street; public notice issued |
In response, Hanover converted Pond Street's three filters to granular activated carbon (GAC) media in phases: Filter #3 first, as a pilot demonstration study approved by MassDEP, going into service October 5, 2021; then Filter #2 on April 27, 2022; then Filter #1 on September 26, 2022. As each filter's GAC media has become exhausted, the town has replaced it — Filter #3's media in October 2023, Filter #2's in May 2024. The Beal and Broadway plants have not exceeded the state standard.
As of the town's most recent public reporting, Hanover's system is meeting the 20 ppt state standard. That's not the end of the story, though: the town is getting ahead of a stricter federal limit that hasn't taken effect yet. A pilot study run at Pond Street between July 2025 and January 2026 compared GAC against ion-exchange (IX) resin; both treatments brought PFOA and PFOS below 2 ppt, with IX showing a longer expected media life. In May 2026, Hanover Town Meeting approved $32 million in borrowing to upgrade PFAS treatment (plus SCADA controls) across all three plants — building on a $1.75 million design appropriation approved in 2024.
| Standard | Limit | Status |
|---|---|---|
| MA PFAS6 (sum of 6 compounds) | 20 ppt | Met as of latest public reporting |
| EPA PFOA (individual) | 4 ppt | Not yet enforced; pilot-tested treatment already achieves <2 ppt |
| EPA PFOS (individual) | 4 ppt | Not yet enforced; pilot-tested treatment already achieves <2 ppt |
ppt = parts per trillion. Sources: Hanover Water Department PFAS public notices (2021, 2023); Hanover PFAS treatment-upgrade update; May 2026 Annual Town Meeting warrant coverage, South Shore News.
How the rules around PFAS in drinking water have changed — and how Hanover's own situation fits into that timeline.
MassDEP finalized an enforceable Maximum Contaminant Level (MCL) of 20 parts per trillion (ppt) for the sum of six PFAS compounds ("PFAS6") — PFOS, PFOA, PFHxS, PFNA, PFHpA, and PFDA. This is the standard the Hanover Water Department is required to meet today, and the one its Pond Street plant exceeded in 2021 and 2023.
Routine monitoring found PFAS6 above the state's 20 ppt standard at the Pond Street plant in 2021 (averaging 22.3 ppt over April–June testing) and again in 2023. Both triggered public notices and corrective GAC treatment, described in detail above.
The EPA's National Primary Drinking Water Regulation (NPDWR) set the first-ever enforceable federal limits for PFAS: 4 ppt each for PFOA and PFOS individually, 10 ppt each for PFHxS, PFNA, and HFPO-DA (GenX), plus a combined Hazard Index limit for mixtures of those and PFBS. Water systems were given until 2027 to complete initial monitoring and until 2029 to come into full compliance.
Rather than waiting for the 2029 compliance deadline, Hanover appropriated $1.75 million in 2024 to design PFAS treatment upgrades, ran a GAC-vs-ion-exchange pilot study at Pond Street through early 2026, and won voter approval in May 2026 for a $32 million bond to upgrade all three treatment plants.
EPA proposed keeping the PFOA and PFOS limits at 4 ppt each, but allowing water systems to request a two-year compliance extension — to 2031 instead of 2029. In a separate proposal, EPA moved to rescind the individual limits for PFHxS, PFNA, and HFPO-DA and the Hazard Index for PFAS mixtures, citing procedural requirements under the Safe Drinking Water Act. The PFOA and PFOS limits themselves were not proposed for rescission. A virtual public hearing was held July 7, 2026, and the public comment period on both proposals runs through July 20, 2026 — check EPA's site directly for the current status before assuming either proposal is final.
Sources: Mass.gov — Massachusetts PFAS Drinking Water Standard (MCL); Federal Register — PFAS National Primary Drinking Water Regulation (April 2024); Federal Register — Extending the Compliance Deadline for PFOA/PFOS MCLs (May 2026); Federal Register — Rescission of Regulatory Determinations for Four PFAS Substances (May 2026).
We don't ask you to take our word for any of this. The underlying reports are public:
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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