Acton Water Supply District, MA
Lead detected, under the action levels
Latest 90th-percentile lead: 3.5 ppb (monitoring period 2026-2026). The federal action level is 15 ppb today and drops to 10 ppb in Nov 2027; EPA's health goal is 0. Lead was measured in sampled homes but the 90th percentile is under both action levels. EPA's health goal for lead is zero, so test your own tap if your home was built before 1986 or anyone in it is pregnant or a young child.
Who runs the water here
Acton Water Supply District serves about 21,285 people through 6,905 service connections, which makes it a large system under EPA's size classes. It is owned by a local government (city, town, county or district) and draws surface water, in Middlesex County, Massachusetts. EPA system ID: MA2002000; phone on file: 9782639107. Call that number and ask whether your address has a lead, galvanized or unknown service line.
Lead results over time
Against the period ending 2025 (3.6 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for Acton Water Supply District is 10 ppb across 13 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2026 | 3.5 ppb |
| 2025 | 3.6 ppb |
| 2024 | 2.9 ppb |
| 2024 | 3.2 ppb |
| 2023 | 4 ppb |
| 2023 | 3 ppb |
| 2022 | 4 ppb |
| 2022 | 6 ppb |
| 2021 | 10 ppb |
| 2021 | 6 ppb |
| 2020 | 3.6 ppb |
| 2020 | 4 ppb |
| 2017 | 10 ppb |
Where this result ranks
Of the 535 Massachusetts systems with a lead result, the median latest reading is 1.7 ppb; 13 are over 15 ppb right now and 66 have gone over at some point. Acton Water Supply District's 3.5 ppb sits at the 75th percentile in Massachusetts and the 85th nationally (higher means more lead).
Neighbouring systems
94 other systems share Middlesex County; 24 of them have a higher latest lead result than Acton Water Supply District. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Lowell Regional Water Utility | 120,418 | 0 (not detected) |
| Cambridge Water Department | 118,214 | 8 ppb |
| Newton Water Dept. (Mwra) | 88,931 | 1.09 ppb |
| Somerville Water Dept. (Mwra) | 81,045 | 6.62 ppb |
| Framingham Water Dept. (Mwra) | 72,362 | 1.74 ppb |
| Malden Water Division (Mwra) | 66,263 | 9.74 ppb |
| Waltham Water Department | 65,218 | 2.24 ppb |
| Medford Water Dept. (Mwra) | 61,700 | 8.31 ppb |
| Everett Water Dept. (Mwra) | 49,075 | 1.25 ppb |
| Arlington Water Dept. (Mwra) | 46,308 | 2.68 ppb |
What to do in your house
Test your own tap with a certified lab first-draw sample; Acton, MA may offer free or low-cost kits through the utility. If your own line is lead, replacing the private side runs about $1,200-$12,300 (EPA average about $4,700). Ask Acton Water Supply District whether it covers that cost before hiring anyone - many utilities now do.
These figures describe homes the utility sampled, not your tap. Only your service line record or a test of your own water answers the question for your house. What a 90th-percentile result does and does not tell you: how to read a lead result. Size matters more than most people expect: small vs large water systems.