Winthrop Water Division, (Mwra), MA
Above the federal action level
Latest 90th-percentile lead: 16.4 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. In the most recent monitoring period, more than 10% of the sampled homes measured above 15 ppb. Use a filter certified to NSF/ANSI 53 for lead for drinking and cooking now, and test your own tap.
Winthrop Water Division, (Mwra) at a glance
Winthrop Water Division, (Mwra) serves about 19,316 people through 4,547 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 Suffolk County, Massachusetts. EPA system ID: MA3346000; phone on file: 6178461341. They can tell you what your service line is made of and whether they pay to replace it.
Every lead result on file
That is up 9.8 ppb from 6.6 ppb in the period ending 2025. The highest 90th-percentile result EPA holds for Winthrop Water Division, (Mwra) is 27.6 ppb across 16 monitoring periods, 6 of them over the 15 ppb action level.
| Period ending | 90th-percentile lead |
|---|---|
| 2026 | 16.4 ppb over 15 |
| 2025 | 6.6 ppb |
| 2024 | 23.2 ppb over 15 |
| 2024 | 8.3 ppb |
| 2023 | 9.26 ppb |
| 2023 | 8.64 ppb |
| 2022 | 11.1 ppb over 10 |
| 2022 | 17.3 ppb over 15 |
| 2021 | 23 ppb over 15 |
| 2021 | 20 ppb over 15 |
| 2020 | 7.4 ppb |
| 2018 | 12.6 ppb over 10 |
| 2018 | 11.5 ppb over 10 |
| 2018 | 27.6 ppb over 15 |
| 2018 | 7.53 ppb |
| 2016 | 9.57 ppb |
How Winthrop Water Division, (Mwra) compares
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. Winthrop Water Division, (Mwra)'s 16.4 ppb sits at the 98th percentile in Massachusetts and the 99th nationally (higher means more lead).
Nearby utilities
4 other systems share Suffolk County; 1 of them has a higher latest lead result than Winthrop Water Division, (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 |
| 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 |
Your move
Use a filter certified to NSF/ANSI 53 for lead on the tap you drink and cook from, now, before you test. Then test your own tap. If your own line is lead, replacing the private side runs about $1,200-$12,300 (EPA average about $4,700). Ask Winthrop Water Division, (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. Systems that went over once often dip back under; here is what that means.