Scwa, North Stonington Division (Nst), CT
Lead detected, under the action levels
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. 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
Scwa, North Stonington Division (Nst) serves about 1,860 people through 255 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 groundwater, in New London County, Connecticut. EPA system ID: CT1020021; phone on file: 860-464-0232. They can tell you what your service line is made of and whether they pay to replace it.
Every lead result on file
Against the period ending 2025 (1.9 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for Scwa, North Stonington Division (Nst) is 2.4 ppb across 5 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2026 | 1.1 ppb |
| 2025 | 1.9 ppb |
| 2025 | 0 (not detected) |
| 2021 | 0.7 ppb |
| 2018 | 2.4 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. Scwa, North Stonington Division (Nst)'s 1.1 ppb sits at the 59th percentile in Connecticut and the 57th nationally (higher means more lead).
Other water systems in New London County
82 other systems share New London County; 32 of them have a higher latest lead result than Scwa, North Stonington Division (Nst). 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
Test your own tap with a certified lab first-draw sample; Gales Ferry, 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 Scwa, North Stonington Division (Nst) 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. Size matters more than most people expect: small vs large water systems.