Montville Water Supply, CT
Lead reported as not detected
Latest 90th-percentile lead: reported as 0 (not detected) (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 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 Montville Water Supply
Montville Water Supply serves about 1,300 people through 561 service connections, which makes it a small system under EPA's size classes. It is owned by a local government (city, town, county or district) and draws surface water, in New London County, Connecticut. EPA system ID: CT0864011; phone on file: 860-848-6711. They can tell you what your service line is made of and whether they pay to replace it.
Montville Water Supply'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 Montville Water Supply is 11.2 ppb across 14 monitoring periods, none of them over 15 ppb (1 over 10 ppb).
| Period ending | 90th-percentile lead |
|---|---|
| 2026 | 0 (not detected) |
| 2025 | 0 (not detected) |
| 2025 | 0 (not detected) |
| 2024 | 1.6 ppb |
| 2024 | 1.8 ppb |
| 2023 | 0 (not detected) |
| 2023 | 1.4 ppb |
| 2022 | 0 (not detected) |
| 2022 | 11.2 ppb over 10 |
| 2021 | 0 (not detected) |
| 2021 | 1.5 ppb |
| 2020 | 1.2 ppb |
| 2020 | 1.2 ppb |
| 2019 | 1.5 ppb |
Where this result ranks
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. Montville Water Supply's reported as 0 (not detected) sits at the 31st percentile in Connecticut and the 28th nationally (higher means more lead). Systems reporting 0 tie at the bottom, so the rank mostly reflects size among them.
Other water systems in New London County
82 other systems share New London County; 44 of them have a higher latest lead result than Montville Water Supply. 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) |
What to do in your house
Look up your address in Montville Water Supply'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 Montville Water Supply 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. Small systems behave differently: why small systems go over more often.