St. Thomas More School-Main System, CT
Exceeded the action level in the past
Latest 90th-percentile lead: 1.1 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
St. Thomas More School-Main System serves about 270 people through 27 service connections, which makes it a very small system under EPA's size classes. It is privately owned and draws groundwater, in New London County, Connecticut. EPA system ID: CT0861251; phone on file: 860-367-4799. Ask them for your address in their service line inventory - every system had to publish one by Oct 2024.
St. Thomas More School-Main System's lead record
That is up 1.1 ppb from 0 ppb in the period ending 2025. The highest 90th-percentile result EPA holds for St. Thomas More School-Main System is 25 ppb across 20 monitoring periods, 1 of them over the 15 ppb action level.
| Period ending | 90th-percentile lead |
|---|---|
| 2026 | 1.1 ppb |
| 2025 | 0 (not detected) |
| 2025 | 0 (not detected) |
| 2024 | 1.5 ppb |
| 2024 | 0 (not detected) |
| 2023 | 0 (not detected) |
| 2023 | 1.5 ppb |
| 2022 | 0 (not detected) |
| 2021 | 0 (not detected) |
| 2021 | 0 (not detected) |
| 2020 | 2 ppb |
| 2020 | 0 (not detected) |
| 2019 | 0 (not detected) |
| 2019 | 0 (not detected) |
| 2018 | 0 (not detected) |
| 2018 | 1.7 ppb |
| 2017 | 3.3 ppb |
| 2017 | 2.5 ppb |
| 2016 | 2.3 ppb |
| 2016 | 25 ppb over 15 |
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. St. Thomas More School-Main System's 1.1 ppb sits at the 59th percentile in Connecticut and the 57th nationally (higher means more lead).
Neighbouring systems
82 other systems share New London County; 32 of them have a higher latest lead result than St. Thomas More School-Main System. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Norwich Public Utilities | 36,163 | 0 (not detected) |
| Groton Utilities | 30,200 | 1.1 ppb |
| New London Dept. Of Public Utilities | 27,620 | 0 (not detected) |
| Waterford Wpca | 16,578 | 1.5 ppb |
| East Lyme Water & Sewer Commission | 15,245 | 0 (not detected) |
| Aquarion-Mystic | 10,788 | 0 (not detected) |
| Jewett City Water Company | 6,840 | 0 (not detected) |
| Colchester Sewer & Water Commission | 4,020 | 0 (not detected) |
| Ctwc - Shoreline Region-Sound View | 3,397 | 0 (not detected) |
| Ledyard Wpca - Ledyard Center | 3,294 | 0 (not detected) |
Your move
Test your own tap with a certified lab first-draw sample; Oakdale, 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 St. Thomas More School-Main 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. 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.