Boston Water And Sewer Commission (Mwra), MA
Exceeded the action level in the past
Latest 90th-percentile lead: 7.96 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. The latest result is under the action level, but this system has gone over 15 ppb before. Lead comes from pipes, not the source water, so a home with a lead service line can still be exposed. Test your own tap.
Who runs the water here
Boston Water And Sewer Commission (Mwra) serves about 675,647 people through 88,895 service connections, which makes it a very large system under EPA's size classes. It is owned by a local government (city, town, county or district) and draws surface water, in Suffolk County, Massachusetts. EPA system ID: MA3035000; phone on file: 6179897000. Ask them for your address in their service line inventory - every system had to publish one by Oct 2024.
Lead results over time
That is down 4.64 ppb from 12.6 ppb in the period ending 2026. The highest 90th-percentile result EPA holds for Boston Water And Sewer Commission (Mwra) is 99.5 ppb across 15 monitoring periods, 5 of them over the 15 ppb action level.
| Period ending | 90th-percentile lead |
|---|---|
| 2026 | 7.96 ppb |
| 2026 | 12.6 ppb over 10 |
| 2025 | 22.5 ppb over 15 |
| 2025 | 9.76 ppb |
| 2024 | 25.2 ppb over 15 |
| 2024 | 8.92 ppb |
| 2024 | 9.98 ppb |
| 2021 | 11.9 ppb over 10 |
| 2021 | 5.8 ppb |
| 2021 | 99.5 ppb over 15 |
| 2021 | 6.88 ppb |
| 2020 | 21.3 ppb over 15 |
| 2018 | 11.7 ppb over 10 |
| 2017 | 12.7 ppb over 10 |
| 2016 | 17.4 ppb over 15 |
Against other Massachusetts systems
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. Boston Water And Sewer Commission (Mwra)'s 7.96 ppb sits at the 92nd percentile in Massachusetts and the 96th nationally (higher means more lead).
Neighbouring systems
4 other systems share Suffolk County; 2 of them have a higher latest lead result than Boston Water And Sewer Commission (Mwra). If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Mwra | 2,580,000 | 5.9 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 |
Your move
Test your own tap with a certified lab first-draw sample; Boston, 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 Boston Water And Sewer Commission (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. The lead result guide covers how utilities pick the homes they sample. Why an old exceedance still matters: over the limit before, under it now.