Pembroke's public water comes entirely from five active groundwater wells operated by the Pembroke Water Division, a department of the Town's Department of Public Works (Water Superintendent Daniel Sullivan). There is no surface reservoir or river intake — every gallon comes out of the ground. Public trackers put the population served at approximately 18,200–18,300 residents (estimates range from 18,188 to 18,251 depending on the source), which is essentially the town's entire population.
Two of the five wells, Hobomock Well and the Bryantville Well, draw from ground naturally high in iron and manganese and require dedicated treatment beyond what the other wells receive. Wells 1–4 are treated with potassium hydroxide for corrosion control and calcium hypochlorite for disinfection; Hobomock and Bryantville additionally go through iron- and manganese-removal treatment before entering the distribution system. The town's distribution network runs about 135 miles of water main, feeding three storage tanks and roughly 1,000 fire hydrants.
This groundwater sits in the same geology that historically fed Pembroke's interconnected network of ponds and cranberry bogs — by 1924, town directories listed 17 cranberry growers, 14 of them in the Bryantville village alone. Those ponds (including Oldham Pond and Stump Pond, pictured on this site) are still used for recreation, as a water source, and for bog irrigation today, though far fewer bogs remain active than a century ago. As of mid-2026, Pembroke was also under an active regional drought advisory, which lowers pond levels and can concentrate naturally occurring minerals in groundwater further.
The most consistent, well-documented issue with Pembroke's water isn't a regulated contaminant at all — it's discoloration. Naturally occurring iron and manganese, built up over decades in the town's older wells and pipes, get stirred loose by biannual system flushing, fire-flow testing, water-main breaks, and nearby construction work, turning tap water visibly brown ("as dark as Coca-Cola," in more than one resident's description).
Two residents who tracked their own incidents through 2024 reported roughly a dozen to twenty discoloration events each over the year, describing ruined laundry loads and water they wouldn't cook or bathe with. Water Superintendent Dan Sullivan has characterized the issue publicly as "an aesthetic concern. It's not a health concern," noting aging water systems across Massachusetts deal with the same thing and that the department is "still trying to get a feel for how often this is happening."
In December 2024, the town presented a $75 million, multi-year infrastructure plan focused on replacing aging water main, with officials aiming for a noticeable improvement within about three years. The department also launched an online form for residents to report discoloration incidents directly, partly to track whether contractor work is a recurring cause.
"Aesthetic, not health" is the DPW's own characterization, not an independent medical judgment — the EPA does not currently classify iron or manganese as health-based drinking water contaminants at the levels typically seen in cases like this, but if your household is dealing with persistent discoloration, a household-level test is the only way to know what's actually in your specific tap.
As with several other South Shore towns, independent public trackers do not agree on Pembroke's violation history, and we think that's worth being upfront about rather than picking whichever version sounds more dramatic.
| Source | What it reports |
|---|---|
| Aggregator tracker A | A Total Coliform Rule (TCR) monitoring violation window from 2010–2015, described as the system's only documented health-based exceedance since 2010 |
| Aggregator tracker B (EWG-sourced) | Zero MCL violations on record; no EPA violations noted; overall water quality graded "B / Good" |
| EPA quarterly compliance snapshot | In compliance with federal health-based standards for the most recently assessed quarter (April–June 2024) |
These are third-party aggregations of EPA SDWIS data, not EPA's database itself, and they don't fully agree with each other. We were also unable to retrieve Pembroke's full 2024 Consumer Confidence Report directly (the link published by the town returned a broken-page error at the time of our research) to independently reconcile these. Rather than presenting one number as fact, we recommend checking EPA's ECHO database directly, or requesting the current Consumer Confidence Report from the Pembroke DPW at (781) 709-1425.
Public sources also don't fully agree on Pembroke's PFAS picture. One aggregator, drawing on EPA's Fifth Unregulated Contaminant Monitoring Rule (UCMR5, 2023–2025) results, reports two detected compounds:
| Compound | Reported level | Regulatory status |
|---|---|---|
| PFHxA | ~4.8 ppt | Monitored under UCMR5; no individual federal or MA PFAS6 limit |
| PFPeA | ~5.7 ppt | Monitored under UCMR5; no individual federal or MA PFAS6 limit |
A second aggregator states plainly that Pembroke "has PFAS monitoring data on record and no PFAS compounds are currently above EPA health-based guidelines," and a summary of the town's own 2024 CCR indicated no PFAS detections at all — though we could not confirm that directly against the primary document, which was unreachable at the link the town published.
What we can say with confidence either way: no public source we found reports PFOA or PFOS — the two compounds with individual enforceable federal limits (4 ppt each) and the two most consistently linked to health effects in research — detected in Pembroke's water at any level. Neither PFHxA nor PFPeA, the two compounds one tracker does report, is part of Massachusetts' regulated six-compound PFAS6 sum (PFOS, PFOA, PFHxS, PFNA, PFHpA, PFDA) or subject to an individual enforceable limit under the 2024 federal rule. Whichever version of the data is most current, Pembroke's PFAS picture today looks meaningfully cleaner than systems where PFOA or PFOS has actually turned up above a legal limit.
ppt = parts per trillion. Sources: EPA UCMR5 occurrence data (2023–2025) as aggregated by public tap-water trackers; Pembroke Water Division's published Consumer Confidence Report summaries.
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. At the time, Massachusetts was among the first states in the country with a legally enforceable PFAS drinking water standard; there was still no federal one. This is the standard the Pembroke Water Division is required to meet today, and public data does not show Pembroke exceeding it.
This nationwide EPA monitoring round is the source of the PFHxA and PFPeA readings referenced above — two compounds monitored because they aren't yet subject to enforceable limits, not because they were flagged as a specific concern for Pembroke.
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. No public data reviewed for this site shows Pembroke's water exceeding any of these limits.
On May 18, 2026, EPA proposed two changes: keeping the PFOA and PFOS limits at 4 ppt each but letting water systems request a two-year compliance extension (to 2031 instead of 2029), and separately, rescinding the individual limits for PFHxS, PFNA, and HFPO-DA and the combined Hazard Index for PFAS mixtures, citing procedural requirements under the Safe Drinking Water Act. EPA held a public hearing on the proposals on July 7, 2026, with the public comment period scheduled to close July 20, 2026; EPA has indicated it intends to finalize the rules before the end of 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); 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 — service lines, home plumbing, and private wells can all change what actually comes out of your tap.
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