Weymouth operates its own independent public water system — EPA/MassDEP Public Water System ID MA4336000 — run by the Weymouth Water Department, a division of the Town's Department of Public Works. Unlike some neighboring South Shore towns, Weymouth doesn't buy finished water wholesale from a neighbor or co-own a joint system; it treats and distributes its own supply from two plants.
The Great Pond Water Treatment Plant (GPWTP), capable of producing up to 8.0 million gallons per day, treats surface water from Great Pond plus a supplemental pumping station drawing from the South Cove of Whitman's Pond — together, about 86% of the town's supply. The Arthur J. Bilodeau Water Treatment Plant (AJBWTP) treats groundwater from five active bedrock wells in the Mill River Aquifer: the Circuit Avenue, Main Street, Libbey, Winter Street #1, and Winter Street #2 wells — about 14% of supply. Drinking water reaches roughly 16,773 metered customer accounts (serving nearly 18,000 buildings) through the town's distribution network. In genuine emergencies only, the system can be supplemented by neighboring Abington, Rockland, Braintree, Hingham, and Quincy — backup capacity, not a routine shared supply.
Population served: public trackers disagree on the exact figure, reporting anywhere from about 55,998 to roughly 58,000 people. We report the range rather than picking whichever number sounds more precise. Trackers also differ slightly on total distribution pipe length — the town's own materials cite figures between about 237 and 245 miles depending on the document and year.
Weymouth's independence has real limits. MassDEP set a "safe yield" for the town's sources at 4.94 million gallons per day, and after the state ordered demand reductions starting in 1994, a 1997 Administrative Consent Order committed the town to holding consumption to 4.51 mgd. That supply constraint — combined with the need to serve the redevelopment of the former South Weymouth Naval Air Station into the "SouthField" mixed-use community — is a major reason the town is now pursuing a roughly 6.7-mile transmission main connection to the regional MWRA water system, routed through Quincy, Braintree, and Weymouth, with a new pump station. Public comment on the project closed May 8, 2026 under the state's MEPA review process. Projected timelines vary by source: town materials point to MWRA water reaching Weymouth and SouthField around January 2030, while other reporting describes pipeline construction running 2027–2029 with full completion "on track for 2031" — we report both rather than picking one.
By every current tracker's account, the Weymouth Water Department's own supply has a clean recent record: EPA ECHO shows zero Safe Drinking Water Act violations across the periods it publishes, and the town's own 2025 Annual Water Quality Report states plainly that the system "had no violations." One independent tracker, PlainEnviro, lists a single historical entry that doesn't appear in the other sources we checked:
| Period | Rule | What was found |
|---|---|---|
| January 1, 1997 | Combined Radium 226/228 (radionuclides) | Treatment Technique (TT) violation, health-based — listed by PlainEnviro's aggregation of SDWIS records; not shown in EPA ECHO's own recent-history views or the current CCR |
| 2019–present | All monitored rules | No violations reported by EPA ECHO, the town's CCRs, or TapWaterData |
We're reporting this disagreement honestly rather than omitting the older record or treating it as current: a nearly 30-year-old entry from one aggregator, absent from the others, is most consistent with an old, long-resolved compliance issue that predates today's more visible online violation databases — not an ongoing problem. Separately, TapWaterData assigns the system a "D" grade based on comparison to its own non-enforceable health-guideline benchmarks (stricter than legal MCLs), while confirming "no MCL violations on record" — a methodology difference worth knowing about before assuming a grade means a legal violation.
Weymouth's own tap water and the PFAS story at the former South Weymouth Naval Air Station are two entirely different things, and conflating them would misrepresent both. Here's what the data actually shows for each:
| Source | What was tested | Result | Applicable limit |
|---|---|---|---|
| Weymouth Water Department (town tap water) | PFAS6 (combined: PFOS, PFOA, PFHxS, PFNA, PFHpA, PFDA) | ND–11.4 ppt, 2025 | 20 ppt (MA PFAS6 MCL) — no violation |
| Weymouth Water Department (unregulated, UCMR5) | PFBA | 2.9 ppt | No established MCL/ORSG |
| Weymouth Water Department (unregulated, UCMR5) | PFBS | 1.2–2.33 ppt | No established MCL/ORSG |
| Weymouth Water Department (unregulated, UCMR5) | PFHxA | 1.6–2.55 ppt | No established MCL/ORSG |
| Mill River Water Takers Association (separate, small local system near South Weymouth) | PFOA | 1.9 ppt | 4 ppt (federal PFOA individual limit) — below limit |
| Former South Weymouth Naval Air Station (on-site groundwater, under CERCLA cleanup) | PFOA / PFOS / combined | ~25,000 ppt / ~27,000 ppt / ~256,000 ppt (2018 sampling) | Thousands of times the 4 ppt federal individual limit — not a public drinking water source |
The Weymouth Water Department's published Consumer Confidence Report gives combined PFAS6 results but doesn't break results down by individual compound (PFOA vs. PFOS specifically), so we can't independently confirm the town's own supply meets the federal 4 ppt individual limits compound-by-compound — only that the combined PFAS6 figure is well under the state's 20 ppt threshold. That's a real limitation of the public reporting, not a claim we're making up.
The former South Weymouth Naval Air Station (now being redeveloped as "SouthField") is a 1,444-acre EPA Superfund site spanning parts of Weymouth, Abington, and Rockland. Decades of firefighting training with aqueous film-forming foam (AFFF) — concentrated at the base's Fire Fighting Training Area and Hangar 1 — left extremely high PFAS levels in on-site groundwater: 2018 sampling found PFOA around 25,000 ppt and PFOS around 27,000 ppt, a combined reading near 256,000 ppt, thousands of times over both the federal 4 ppt individual limit and MA's 20 ppt combined standard.
This is not part of Weymouth's public drinking water supply. The contamination sits in groundwater at and around the former base, under active federal cleanup (a "Basewide PFAS" Operable Unit, OU27, opened in June 2018), not in the Mill River Aquifer wells the town actually uses. A time-critical removal action for PFAS-contaminated soil near Building 96 Fire Station and Hangar 1 was completed in January 2025, and broader investigation across the site continues. It's a genuinely serious, well-documented contamination story — just not the same story as "is Weymouth's tap water safe," which the town's own testing answers separately and, so far, favorably.
Sources: EPA Superfund Site Profile — South Weymouth Naval Air Station; Navy BRAC PMO PFAS program materials.
MassDEP's Source Water Assessment Program (SWAP) report for Weymouth rates the Great Pond surface supply as having moderate susceptibility to contamination, citing residential fuel storage and landscaping practices in the watershed. It rates the groundwater sources (Mill River Aquifer wells) and the South Cove of Whitman's Pond as having high susceptibility, because current land use in those recharge areas includes gas stations and industrial businesses. A high susceptibility rating describes vulnerability to future contamination based on nearby land use — it is not, itself, evidence that contamination has occurred; the town's actual testing results above are the relevant check on that.
Separately, unregulated testing found sodium at 43.1–152 ppm, above the state's non-enforceable Office of Research and Standards Guideline (ORSG) of 20 ppm. This isn't a legal violation — there's no MCL for sodium — but it's worth knowing if you or someone in your household is on a sodium-restricted diet.
Weymouth's 2025 tap sampling for lead came back clean: a range of 0–4.8 ppb across 30 approved sample sites, with a 90th-percentile result of 1 ppb — well under the 15 ppb federal action level. But the town's separate, mandatory service line material inventory (due to MassDEP by October 16, 2024) is not fully resolved: of roughly 18,000 service connections, a few hundred records remain classified "unknown" because historical documentation didn't specify the pipe material. The Water Department says most of those unknowns are unlikely to be lead based on the era in which they were installed, but hasn't confirmed that compound-by-compound, and is actively asking residents in unknown, lead, or "galvanized requiring replacement" categories to help verify their own service line material. That's a more honest, in-progress result than a fully clean inventory — and worth knowing if your property falls into one of those categories.
How the rules around PFAS in drinking water have actually changed over the past several years — and where they stand right now.
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 Weymouth Water Department has consistently tested well under (ND–11.4 ppt in 2025).
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. Weymouth's own CCR doesn't break out individual PFOA/PFOS results, so full compliance with this specific rule can't be independently confirmed from public reporting alone — though the combined PFAS6 figure is a reassuring sign.
EPA proposed two changes. The first (Docket EPA-HQ-OW-2025-1742) would keep the PFOA/PFOS limits at 4 ppt each but let water systems request a two-year compliance extension — to 2031 instead of 2029 — while requiring systems measuring 12 ppt or higher to take short-term mitigation action in the meantime. The second (Docket EPA-HQ-OW-2025-0654) would rescind the individual limits for PFHxS, PFNA, and HFPO-DA and the Hazard Index for PFAS mixtures, leaving the PFOA/PFOS limits untouched. EPA held a virtual public hearing on July 7, 2026.
The combined comment dockets remain open through July 20, 2026 — five days from today — with well over 15,000 comments already submitted. Neither proposal is final. EPA has indicated it intends to act on the rescission proposal sometime in 2026; check EPA's site directly for the current status before assuming either change has taken effect. For Weymouth, whose own municipal PFAS6 results are already well under both the state and federal thresholds, this rulemaking is lower-stakes than it would be for a town with an actual exceedance — but it's still worth tracking, since the federal individual-compound limits are the ones the town's own reporting can't fully confirm compliance with today.
Sources: Mass.gov — Massachusetts PFAS Drinking Water Standard (MCL); Federal Register — PFAS National Primary Drinking Water Regulation (April 2024); EPA — Proposed PFOA and PFOS Compliance Extension Rule; EPA — Proposed PFAS Rescission Rule.
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 — your home's plumbing, fixtures, and how long water sits in your pipes can all change what actually comes out of your tap.
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