Braintree Water & Sewer's drinking water comes from the Great Pond Reservoir System, a surface-water supply reaching an estimated 39,143 residents (EPA/SDWIS Public Water System #MA4040000). Water enters the Upper Reservoir via Narroway Brook and feeds the Lower Reservoir by gravity, where it enters Braintree's Treatment Plant. The Richardi Reservoir, fed by the Farm River, is a supplemental source pumped in through a dedicated 24-inch pipeline when the main reservoir runs low. In an emergency, Braintree can also draw water from Quincy, Weymouth, Randolph, Holbrook, or the MWRA.
Great Pond itself straddles the Braintree/Randolph town line, and its waters have been shared among Braintree, Randolph, and Holbrook since an 1885 Massachusetts legislative act divided the pond's supply among the three towns. That shared history is why the three communities jointly govern the reservoir today through the Tri-Town Board of Water Commissioners — but historically, Braintree and the neighboring Randolph/Holbrook Joint Water Board have run separate intakes and treatment plants on opposite sides of the same pond, each with its own permit, its own treatment process, and its own compliance record. Braintree's numbers on this page describe only Braintree's own system, not Randolph's or Holbrook's.
That is changing: in 2019 the three towns formed the Tri-Town Water District to build one new consolidated regional treatment plant. Construction began in November 2022, and after MassDEP approval, the new Tri-Town Regional Water Treatment Plant began blending water into Braintree's, Randolph's, and Holbrook's distribution systems starting July 6, 2026 — a transition expected to take about a month, with temporary changes in taste, pressure, or clarity possible in the meantime. See our Updates page for more on what this means.
Because it draws from a pond and its tributary brooks rather than deep groundwater wells, Great Pond water carries more naturally occurring organic matter than a typical well supply. Braintree's plant is built around that reality: coagulation and flocculation to pull organic material out of suspension, filtration, activated carbon treatment, and chlorination for disinfection, plus pH adjustment and corrosion control before the water reaches your tap. That heavier treatment train is also why chlorine taste tends to be more noticeable in Braintree than in a town supplied by groundwater alone.
According to EPA's Safe Drinking Water Information System (SDWIS) federal reporting, Braintree's water system has one health-based Maximum Contaminant Level (MCL) violation on record: a Total Coliform Rule violation in July 2000, which triggered a required public notification and was resolved. SDWIS shows no additional health-based violations in the roughly 25 years since.
SDWIS also lists a longer trail of non-health-based monitoring and reporting violations — gaps in volatile organic chemical and nitrate monitoring between 1998 and 2006, and Consumer Confidence Report reporting issues logged in 2009, 2011, and 2022, all since returned to compliance. A separate Lead and Copper Rule monitoring violation from October 2013 involved late-submitted results from two schools; the underlying samples were within the legal limit and posed no known health risk. SDWIS's federal reporting tool also currently lists an open, non-health-based "inadequate reporting" item tied to Consumer Confidence Report formatting, dated July 2, 2025 — we're presenting this as we found it rather than omitting it, and will update this page if and when it's marked resolved.
Legal compliance is not the same as zero risk, and a clean recent record doesn't erase an older violation. The EPA sets MCLs based on what's feasible to treat at scale across an entire water system — not necessarily the level with zero associated health risk for every individual.
Massachusetts regulates six PFAS compounds together as "PFAS6" (PFOS, PFOA, PFHxS, PFNA, PFHpA, and PFDA), with a combined Maximum Contaminant Level of 20 parts per trillion, based on a running annual average rather than any single sample. Braintree's 2025 running annual average was 19.24 ppt — below the state limit, and not a violation. One individual monthly sample did reach 20.69 ppt, above the 20 ppt standard, but because compliance is judged on the four-quarter average rather than a single month, this did not constitute a violation.
| Measure | Result | MA PFAS6 MCL | Status |
|---|---|---|---|
| 2025 running annual average | 19.24 ppt | 20 ppt | Below MCL — not a violation |
| Highest single monthly sample (2025) | 20.69 ppt | 20 ppt | Above 20 ppt, but RAA governs compliance |
Source: Braintree Water & Sewer 2025 Water Quality Report (Consumer Confidence Report).
Separately, EPA's Fifth Unregulated Contaminant Monitoring Rule (UCMR5), conducted in 2023–2024, requires large systems to test for a rotating list of PFAS and other emerging contaminants that don't yet carry enforceable federal limits. Braintree's UCMR5 testing detected five PFAS compounds at or above EPA's minimum reporting level:
| Compound | Average level | Range | EPA individual limit | Status |
|---|---|---|---|---|
| PFOS | 7.6 ppt | 6.2 – 8.5 ppt | 4 ppt | Above EPA health-based limit |
| PFOA | 4.7 ppt | 4.4 – 5.3 ppt | 4 ppt | Above EPA health-based limit |
| PFPeA | 4.0 ppt | 3.5 – 5.0 ppt | No individual MCL | Monitored, not yet regulated |
| PFHxA | 3.7 ppt | 3.1 – 4.2 ppt | No individual MCL | Monitored, not yet regulated |
| PFBS | 3.0 ppt | 3.0 ppt | No individual MCL | Monitored, not yet regulated |
ppt = parts per trillion. The EPA's 2024 federal limit for PFOA and PFOS individually is 4 ppt each. Every UCMR5 sample of both PFOS and PFOA in Braintree's testing window, including the low end of each range, came in at or above that 4 ppt figure. Source: EPA UCMR5 occurrence data, 2023–2024, as reported in Braintree's 2025 Consumer Confidence Report.
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 Braintree's system is required to meet today, and the one its 19.24 ppt running annual average is measured against.
As detailed above, this nationwide EPA monitoring round is what actually produced Braintree's PFOA average of 4.7 ppt and PFOS average of 7.6 ppt — both above the individual federal limit that would be finalized the following year, though there was no enforceable federal limit for either compound yet at the time of testing.
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.
On May 18, 2026, 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. EPA held a public hearing on the proposals on July 7, 2026, and public comment remains open through July 20, 2026, with EPA stating an intent to finalize both rules before the end of 2026. Neither proposal is final as of this writing — check EPA's site directly for the current status before assuming either has been finalized.
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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