Windham Water Works, CT
Lead reported as not detected
Latest 90th-percentile lead: reported as 0 (not detected) (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. The latest 90th-percentile result was reported as 0 (not detected at the lab's limit). That says the sampled homes were low, not that your home has no lead service line. Check your utility's service line inventory for your address.
About Windham Water Works
Windham Water Works serves about 21,214 people through 4,956 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 Windham County, Connecticut. EPA system ID: CT1630011; phone on file: 860-465-3086. Call that number and ask whether your address has a lead, galvanized or unknown service line.
Windham Water Works's lead record
That is down 4.3 ppb from 4.3 ppb in the period ending 2025. The highest 90th-percentile result EPA holds for Windham Water Works is 5 ppb across 14 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2025 | 0 (not detected) |
| 2025 | 4.3 ppb |
| 2024 | 0 (not detected) |
| 2023 | 0 (not detected) |
| 2022 | 0 (not detected) |
| 2022 | 2.4 ppb |
| 2021 | 0 (not detected) |
| 2020 | 0 (not detected) |
| 2019 | 3.7 ppb |
| 2019 | 0 (not detected) |
| 2018 | 0 (not detected) |
| 2017 | 0 (not detected) |
| 2016 | 5 ppb |
| 2016 | 0 (not detected) |
Against other Connecticut systems
Of the 493 Connecticut systems with a lead result, the median latest reading is 0.8 ppb; 2 are over 15 ppb right now and 49 have gone over at some point. Windham Water Works's reported as 0 (not detected) sits at the 37th percentile in Connecticut and the 39th nationally (higher means more lead). Systems reporting 0 tie at the bottom, so the rank mostly reflects size among them.
Nearby utilities
45 other systems share Windham County; 25 of them have a higher latest lead result than Windham Water Works. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Putnam Water Pollution Control Authority | 7,300 | 0 (not detected) |
| Ctwc - Crystal System | 6,378 | 2.1 ppb |
| Ctwc - Gallup System | 2,538 | 2.3 ppb |
| Ctwc - Plainfield System | 1,713 | 0 (not detected) |
| Ctwc - Thompson System | 1,070 | 1.1 ppb |
| Woodstock Academy South Campus | 620 | 7.9 ppb |
| Pomfret School | 400 | 0 (not detected) |
| Ctwc - Ashford Park Division | 334 | 0 (not detected) |
| Wyndham Park Apartments | 312 | 1.4 ppb |
| Sterling Water System | 308 | 0.8 ppb |
What to do in your house
Look up your address in Windham Water Works's service line inventory. If it says lead, galvanized or unknown, test your tap. If your own line is lead, replacing the private side runs about $1,200-$12,300 (EPA average about $4,700). Ask Windham Water Works 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. A zero today does not rule out a jump later - the rules are tightening in 2027.