Sterling Water System, CT
Lead detected, under the action levels
Latest 90th-percentile lead: 0.8 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
Sterling Water System serves about 308 people through 90 service connections, which makes it a very small system under EPA's size classes. It is owned by a local government (city, town, county or district) and draws groundwater, in Windham County, Connecticut. EPA system ID: CT1360011; phone on file: 508-564-2904. Call that number and ask whether your address has a lead, galvanized or unknown service line.
Sterling Water System's lead record
Against the period ending 2025 (0 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for Sterling Water System is 11.4 ppb across 11 monitoring periods, none of them over 15 ppb (1 over 10 ppb).
| Period ending | 90th-percentile lead |
|---|---|
| 2026 | 0.8 ppb |
| 2025 | 0 (not detected) |
| 2024 | 0.9 ppb |
| 2023 | 11.4 ppb over 10 |
| 2022 | 7.5 ppb |
| 2021 | 6.4 ppb |
| 2020 | 3.5 ppb |
| 2019 | 5.3 ppb |
| 2018 | 0 (not detected) |
| 2017 | 5.7 ppb |
| 2016 | 5 ppb |
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. Sterling Water System's 0.8 ppb sits at the 50th percentile in Connecticut and the 48th nationally (higher means more lead).
Nearby utilities
45 other systems share Windham County; 21 of them have a higher latest lead result than Sterling Water System. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Windham Water Works | 21,214 | 0 (not detected) |
| 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 |
Next steps for Oneco, CT
Test your own tap with a certified lab first-draw sample; Oneco, CT 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 Sterling Water System 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.