Mwra, MA
Lead detected, under the action levels
Latest 90th-percentile lead: 5.9 ppb (monitoring period 2025-2025). 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
Mwra serves about 2,580,000 people through 186 service connections, which makes it a very large system under EPA's size classes. It is owned by the state and draws surface water, in Suffolk County, Massachusetts. EPA system ID: MA6000000; phone on file: 6172426000. Ask them for your address in their service line inventory - every system had to publish one by Oct 2024.
Mwra's lead record
Against the period ending 2024 (6.9 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for Mwra is 10.8 ppb across 10 monitoring periods, none of them over 15 ppb (1 over 10 ppb).
| Period ending | 90th-percentile lead |
|---|---|
| 2025 | 5.9 ppb |
| 2024 | 6.9 ppb |
| 2023 | 10.8 ppb over 10 |
| 2022 | 7.33 ppb |
| 2021 | 8.56 ppb |
| 2020 | 6.47 ppb |
| 2019 | 7.97 ppb |
| 2018 | 9.73 ppb |
| 2017 | 8.6 ppb |
| 2016 | 6.9 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. Mwra's 5.9 ppb sits at the 88th percentile in Massachusetts and the 93rd nationally (higher means more lead).
Neighbouring systems
4 other systems share Suffolk County; 3 of them have a higher latest lead result than Mwra. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Boston Water And Sewer Commission (Mwra) | 675,647 | 7.96 ppb |
| Revere Water Division (Mwra) | 62,186 | 31.9 ppb |
| Chelsea Water Dept. (Mwra) | 40,787 | 5.38 ppb |
| Winthrop Water Division, (Mwra) | 19,316 | 16.4 ppb |
Next steps for Chelsea, MA
Test your own tap with a certified lab first-draw sample; Chelsea, 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 Mwra 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. Why sampled homes are the worst-case ones is in the guide to reading the number. The action level is dropping - the 10 ppb rule from 2027.