Milton has no water source of its own. The Milton Water Department — EPA/MassDEP Public Water System ID MA3189000, run by the Town's Department of Public Works at 525 Canton Avenue — purchases 100% of its finished, already-treated drinking water wholesale from the Massachusetts Water Resources Authority (MWRA). That water originates at the Quabbin Reservoir (roughly 412 billion gallons of storage, about 65 miles west of Boston) and the Wachusett Reservoir (about 65 billion gallons, 35 miles west), together capable of providing around 250 million gallons a day to the MWRA's 53-community service area, which serves over 2.5 million people. Milton doesn't operate its own treatment plant or wells; its role is distribution — moving MWRA water through roughly 130 miles of local mains, about 1,200 hydrants, and roughly 2,300 gate valves to nearly 8,600–9,000 metered service connections.
Population served: EPA's SDWIS/ECHO records list 28,630 for PWS ID MA3189000; the MWRA's own community page rounds this to approximately 28,000. Service connection counts likewise vary slightly by source and year — SDWIS lists 8,584, while the Town's 2023 reporting describes "nearly 9,000." We report both rather than picking whichever figure sounds more precise.
Because Milton's water is 100% purchased, already-treated MWRA supply, most of what determines its quality happens upstream, at the reservoirs and MWRA's own Carroll and Walnut Hill treatment facilities — not at anything Milton's own Water Department does locally. That's the main reason Milton's water quality profile looks so different from towns running their own wells or local surface water systems: the protective work (a large, sparsely developed watershed with strict land-use controls around both reservoirs) has already been done at a regional level, long before the water reaches a Milton tap.
EPA's SDWIS/ECHO federal database lists six violation records for Milton's system (PWS ID MA3189000) going back to 1992. All but one are old, resolved Treatment Technique (TT) items with compliance periods beginning in 1992, 1993, 2000, and 2007 — each one marked "returned to compliance" by EPA, with resolution dates between April 2001 and March 2008. The remaining record is a Monitoring & Reporting (MR) violation, not health-based, with a compliance period beginning November 2017.
| Compliance period begins | Type | Health-based? | Status in EPA's data |
|---|---|---|---|
| Jan. 1992 | Treatment Technique | Yes | Returned to compliance, April 2001 |
| Jan. 1993 | Treatment Technique | Yes | Returned to compliance, April 2001 |
| Jan. 2000 | Treatment Technique | Yes | Returned to compliance, April 2001 |
| Jan. 2001 | Treatment Technique | Yes | Returned to compliance, April 2002 |
| Jan. 2007 | Treatment Technique | Yes | Returned to compliance, March 2008 |
| Nov. 2017 | Monitoring & Reporting | No | Listed with an open compliance status code in EPA's public data; no return-to-compliance date shown |
We're reporting the 2017 entry honestly rather than guessing at it: EPA's public SDWIS data lists it with an "open" compliance status and no resolution date, but Monitoring & Reporting violations are frequently paperwork/reporting-deadline issues that get resolved without EPA's federal mirror database being promptly updated — a known lag in this specific data system. We could not independently confirm from public records alone whether this reflects an actual ongoing gap today or a stale federal record; we're flagging the uncertainty rather than picking a version that sounds more dramatic or more reassuring. None of the five Treatment Technique violations shown above appear in Milton's current standing with MassDEP, and the Town's own 2023 water quality letter reports no Total Coliform Rule violations for that year. Source: EPA Envirofacts/SDWIS (PWSID MA3189000).
Because Milton draws 100% finished water from the MWRA, its PFAS profile is the MWRA's PFAS profile — there's no separate Milton-specific PFAS test to report, since the Town doesn't operate independent treatment or source monitoring. That MWRA-wide record is genuinely clean:
| Compound(s) | What MWRA testing shows | Applicable limit |
|---|---|---|
| PFAS6 (combined: PFOS, PFOA, PFHxS, PFNA, PFHpA, PFDA) | Sum has come back at zero/non-detect in recent system-wide testing rounds | 20 ppt (MA PFAS6 MCL) — well below the limit |
| PFOA / PFOS (Carroll Treatment Plant, Oct. 2023 sampling) | 1.99 ppt / 1.65 ppt — the highest single-round readings reported to date at that plant | 4 ppt each (federal individual MCLs) — below limit, but the closest the system has come |
| 6:2 FTS (unregulated PFAS, a PFOS-replacement compound) | Detected at up to 6.2 ppt — the highest reported value for any individual PFAS compound in MWRA water to date | No established MCL or ORSG |
| PFHxA, PFBS (unregulated, UCMR5-type monitoring) | Detected at trace/low levels in some rounds | No established MCL or ORSG |
This is a genuinely reassuring result relative to both the Massachusetts 20 ppt PFAS6 standard and the federal 4 ppt individual PFOA/PFOS limits — not a manufactured one. The one thing worth watching, rather than worrying about today, is that unregulated PFAS replacement compounds like 6:2 FTS have no enforceable limit yet; if federal or state regulators eventually set one, it's a number worth checking back on. Sources: MWRA Annual Water Quality Test Results (Full Service); Sierra Club Massachusetts chapter reporting on MWRA PFAS monitoring data.
Milton's most recent published tap sampling (September 2023) found lead at a 90th-percentile level of 6.6 ppb across 20 sample sites — well under the federal action level of 15 ppb. The full range was wider: 0.075 to 20.7 ppb, meaning 1 of the 20 individual samples came back above 15 ppb even though the legally relevant 90th-percentile figure did not. Copper came back at a 90th percentile of 137 ppb (range 6.32–190 ppb), comfortably under its 1,300 ppb action level, with no samples exceeding it.
Lead in tap water almost always comes from a home's own plumbing or service line, not from the source reservoir, which is exactly why Milton's separate Lead Service Line Inventory and Replacement Program is the more relevant local story than reservoir water quality. The Town submitted its full inventory and replacement plan to MassDEP in October 2024, and is now running a funded 2026 construction program: replacing lead service lines at roughly 40 properties and conducting about 500 test-pit inspections to verify service lines still listed as "unknown" material. Replacement happens at no cost to the homeowner where a line is confirmed lead, partly funded through a 25% MWRA grant plus 0% interest loans, with contractor E.B. Rotondi and a full-time onsite resident engineer from CDM Smith. Residents can check their own property's listed service line material using the Town's interactive map.
Sources: Milton Water Department community letter (2023 data); Town of Milton Lead Service Line Inventory and Replacement Program page and October 2024 Service Line Replacement 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. This is the standard the MWRA system supplying Milton has consistently tested well under.
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. The MWRA's own Carroll plant readings (1.99 ppt PFOA, 1.65 ppt PFOS as of its highest round to date) sit comfortably under these 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 Milton, 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 service line material can all change what actually comes out of your tap.
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