The Town of Plymouth Water Division — EPA/MassDEP Public Water System ID MA4239000, run by the Town's Department of Public Works — supplies municipal water to the northern and central parts of town: the area between Federal Furnace Road and the Kingston/Carver boundaries, Plymouth Center, Chiltonville, Manomet, and Cedarville east of Route 3 down to the Bourne line. The system draws 100% groundwater from gravel-packed wells tapping the Plymouth-Carver Sole Source Aquifer, a regional aquifer the EPA formally designated in 1990 — one of the first such designations in New England, reflecting the fact that Plymouth and several neighboring towns have no practical alternate drinking water source.
Well count: sources vary. WaterZen's public-data summary lists 12 gravel-packed wells at 10 locations; the Plymouth Independent's 2026 reporting and the Community Land and Water Coalition both describe 13 major wells (the Independent puts them "from the Carver line in West Plymouth to Cedarville," the Coalition citing 11 locations). We report the range rather than picking one figure, since well counts can shift as sources are added, retired, or reclassified.
Population served: EPA/SDWIS-derived trackers (tapsafe.org, EWG) report 40,362; WaterZen's summary reports 41,499. Plymouth Independent's 2026 reporting describes "approximately 44,000 of Plymouth's [then roughly] 61,000 residents" on municipal water — a rounder, more recent estimate reflecting the town's continued growth (the U.S. Census Bureau's 2024 estimate puts the town's total population at 63,953, making Plymouth the 18th-most-populous municipality in Massachusetts). We report all three rather than picking whichever sounds most precise.
Not everyone in Plymouth is on this system. The town is large and geographically spread out, and several private and community water systems operate independently within its borders — most notably the Pinehills development's own water system, a private community water supply that Aquarion Water Company (a private, investor-owned utility) formally acquired in August 2023, serving roughly 2,700 customer connections with a planned build-out of around 3,100. Additional private and community wells serve the Redbrook and Ponds of Plymouth developments. This site focuses on the Town of Plymouth Water Division's own municipal system (PWS ID MA4239000), which serves the largest share of Plymouth residents, and notes these other systems' existence rather than treating Plymouth as having a single uniform water supply.
Public trackers disagree on the exact count here, and we think it's worth reporting both versions rather than picking whichever sounds more dramatic or more reassuring. One public compilation (tapsafe.org, drawing on EPA ECHO/SDWIS over a 10-year lookback) lists three non-health-based violations; a separate ECHO-derived summary covering a narrower window (April 2019–June 2022) found one. Both agree on the type: paperwork and reporting violations, not health-based contamination findings.
| Compliance period begins | Type | Health-based? | Status |
|---|---|---|---|
| July 2014 | Consumer Confidence Report — failure to report | No | Resolved |
| July 2017 | Consumer Confidence Report — failure to report | No | Resolved |
| October 2019 (some trackers list this window as extending to June 2022) | Lead and Copper Rule — monitoring/reporting | No | Resolved |
No health-based Maximum Contaminant Level (MCL) violation appears in any source we checked. For EPA's most recently assessed quarter (April–June 2024), Plymouth's system was reported in full compliance with federal health-based drinking water standards. Sources: tapsafe.org (EPA ECHO/SDWIS compilation); EPA Envirofacts/SDWIS, PWS ID MA4239000.
The Plymouth Water Division tests a broad panel — the Town's own reporting describes testing for 29 PFAS compounds, though its public PFAS results page details the 8 that are federally and state-regulated. As of the most recent round (October 2024), only two of Plymouth's wells showed any regulated PFAS detection at all, and both were trace-level PFOA with everything else non-detect:
| Well | Compound(s) detected | Reading | Applicable limit |
|---|---|---|---|
| Wannos Pond Well | PFOA (all others non-detect) | 2.39 ppt | 4 ppt (federal PFOA); 20 ppt (MA PFAS6) |
| North Plymouth Well | PFOA (all others non-detect; PFNA/PFHxS/PFBS/HFPO-DA show only trace Hazard Index values of 0.0032 each) | 1.93 ppt | 4 ppt (federal PFOA); 20 ppt (MA PFAS6) |
| All other tested wells | No regulated PFAS detected | Non-detect | — |
Both readings are comfortably below the federal 4 ppt individual PFOA/PFOS limit and Massachusetts' 20 ppt combined PFAS6 standard — and since only one compound was detected at either well, the combined PFAS6 sum at each is effectively the same as the single PFOA reading. The Town's own PFAS page states it "expects that we would be in compliance should MassDEP adopt the same standards that EPA just adopted," reflecting confidence in the margin under both current frameworks. This is a genuinely clean result, not a manufactured one. Source: Town of Plymouth PFAS results page (October 2024 data).
One item worth naming rather than glossing over: Plymouth Municipal Airport appears on general lists of Massachusetts municipal airports with a historical firefighting-foam training use, a known nationwide source of PFAS groundwater contamination near other airports and military sites (Joint Base Cape Cod being the best-known regional example, over 20 miles away). We found no public data or reporting tying a specific PFAS detection in any of Plymouth's tested municipal wells to the airport, and the two wells with any detection (Wannos Pond, North Plymouth) are not the wells closest to it. We're flagging this as background context worth knowing, not as an unresolved contamination finding — the town's actual tested wells come back clean.
Plymouth's most recent lead sampling found a 90th-percentile result of 0.0035 mg/L (3.5 ppb) — about 23% of the federal action level of 15 ppb, and a notably clean result compared to many public water systems. The Environmental Working Group's independent analysis of Plymouth's data separately flags nine contaminants detected at levels that are legal (below every enforceable MCL) but above EWG's own stricter, non-enforceable health guidelines: a group of chlorination byproducts (bromodichloromethane, bromoform, chloroform, dibromochloromethane, and total trihalomethanes), hexavalent chromium, nitrate, combined radium, and tetrachloroethylene (PCE).
This isn't a violation or an exceedance — every one of these readings falls under its legal limit. It's the kind of finding that shows up on most public water systems that disinfect their water (trihalomethanes are a routine byproduct of chlorination) and is worth naming honestly rather than omitting just because nothing here is against the law. EWG's guidelines are intentionally more conservative than EPA's enforceable standards, which is exactly why a compound can appear on this list without representing a compliance problem. Source: EWG Tap Water Database, PWS ID MA4239000.
Plymouth's water source, the Plymouth-Carver Sole Source Aquifer, underlies not just Plymouth but Carver, Kingston, Wareham, Plympton, Middleborough, and Bourne as well — a USGS hydrogeological study even refers to part of this system as the "Plymouth-Carver-Kingston-Duxbury Aquifer System," reflecting how far the same regional groundwater resource extends. Given how large Plymouth is and how close it sits to Kingston, Duxbury, and Carver, we specifically checked whether Plymouth's water system has any actual shared-infrastructure, wholesale purchase, or interconnection relationship with those towns, rather than assuming either way.
We found none. Every town we could confirm information for — including Kingston and Duxbury, both already covered elsewhere in this Water Watch network — operates its own independent wells, its own distribution system, and its own EPA Public Water System ID drawing from the same shared regional aquifer. Sharing an aquifer is a hydrogeological fact, not an operational connection: what happens in one town's wells doesn't automatically show up in another's water bill or CCR. (Duxbury, for comparison, does have a real, if informally documented, intermunicipal water purchase arrangement — but that one is with Marshfield, not Plymouth.) That independence cuts both ways for Plymouth: its water quality isn't at the mercy of a neighboring town's contamination, but conversely, protecting the shared aquifer's recharge areas is a genuinely regional challenge that no single town's water department can manage alone.
That regional-resource dynamic is exactly what's driving Plymouth's own most distinctive local story right now: with the whole town depending on one aquifer and no backup source, 2026 reporting by the Plymouth Independent describes real local disagreement over whether commercial development, sand and gravel mining (488,000 cubic yards approved at one Route 3 site alone), and tree clearing near the aquifer's recharge areas could put long-term pressure on the same water quality picture that tests clean today. See our Updates page for the full story.
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 Plymouth's system has tested well under since testing began.
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. Plymouth's own highest readings to date (2.39 ppt and 1.93 ppt PFOA) sit comfortably under the new individual limits.
EPA proposed two changes. The first 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. The second 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, and said it intends to finalize both rules before the end of 2026.
The combined comment dockets closed on July 20, 2026, with well over 15,000 comments submitted across both proposals. As of today, EPA has not announced a final decision on either the compliance-extension rule or the rescission rule; the agency has said it intends to act before the end of 2026, but the current legal baseline remains the April 2024 rule as written. For Plymouth, whose supply already tests well under both the state and federal PFAS thresholds today, this rulemaking mostly affects paperwork timelines rather than anything that would change what's actually in the water — but it's worth checking EPA's site directly for the current status before assuming either proposal has taken effect.
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 which well serves your neighborhood can all change what actually comes out of your tap.
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