Walworth Waterworks, WI
Lead detected, under the action levels
Latest 90th-percentile lead: 6.3 ppb (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. 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
Walworth Waterworks serves about 2,304 people through 853 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 Walworth County, Wisconsin. EPA system ID: WI2650149. Ask the utility on your bill for your address in their service line inventory.
Every lead result on file
That is down 3 ppb from 9.3 ppb in the period ending 2023. The highest 90th-percentile result EPA holds for Walworth Waterworks is 12 ppb across 5 monitoring periods, none of them over 15 ppb (1 over 10 ppb).
| Period ending | 90th-percentile lead |
|---|---|
| 2025 | 6.3 ppb |
| 2023 | 9.3 ppb |
| 2023 | 9.2 ppb |
| 2022 | 4.9 ppb |
| 2017 | 12 ppb over 10 |
Where this result ranks
Of the 947 Wisconsin systems with a lead result, the median latest reading is 1.33 ppb; 6 are over 15 ppb right now and 71 have gone over at some point. Walworth Waterworks's 6.3 ppb sits at the 92nd percentile in Wisconsin and the 94th nationally (higher means more lead).
Other water systems in Walworth County
26 other systems share Walworth County; 5 of them have a higher latest lead result than Walworth Waterworks. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Whitewater Waterworks | 14,000 | 10 ppb |
| Elkhorn Waterworks | 10,317 | 13 ppb |
| Delavan Waterworks | 9,028 | 10 ppb |
| Lake Geneva Utility Commission | 7,107 | 8 ppb |
| East Troy Waterworks | 5,054 | 4.4 ppb |
| Bloomfield, Village Of | 4,071 | 1.95 ppb |
| Lake Como Sanitary Dist 1 | 3,038 | 2.5 ppb |
| Genoa City Waterworks | 2,766 | 4.56 ppb |
| Williams Bay Waterworks | 2,601 | 45 ppb |
| Geneva National Community Services | 2,250 | 0.71 ppb |
Your move
Test your own tap with a certified lab first-draw sample; Walworth, WI 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 Walworth Waterworks 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. Why sampled homes are the worst-case ones is in the guide to reading the number. The action level is dropping - the 10 ppb rule from 2027.