Potosi Waterworks, WI
Lead detected, under the action levels
Latest 90th-percentile lead: 1.72 ppb (monitoring period 2023-2023). 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
Potosi Waterworks serves about 718 people through 265 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 Grant County, Wisconsin. EPA system ID: WI1220117. Ask the utility on your bill for your address in their service line inventory.
Lead results over time
Against the period ending 2020 (1.67 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for Potosi Waterworks is 4.14 ppb across 3 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2023 | 1.72 ppb |
| 2020 | 1.67 ppb |
| 2017 | 4.14 ppb |
How Potosi Waterworks compares
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. Potosi Waterworks's 1.72 ppb sits at the 57th percentile in Wisconsin and the 67th nationally (higher means more lead).
Neighbouring systems
27 other systems share Grant County; 7 of them have a higher latest lead result than Potosi Waterworks. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Platteville Waterworks | 12,268 | 10.3 ppb |
| Lancaster Waterworks | 3,907 | 1.8 ppb |
| Boscobel Waterworks | 3,237 | 1.1 ppb |
| Fennimore Waterworks | 2,507 | 1.61 ppb |
| Cuba City Waterworks | 2,141 | 0 (not detected) |
| Muscoda Waterworks | 1,453 | 2.64 ppb |
| Hazel Green Waterworks | 1,193 | 2.83 ppb |
| Dickeyville Waterworks | 1,069 | 0 (not detected) |
| Cassville Waterworks | 777 | 3.24 ppb |
| Montfort Waterworks | 718 | 1.1 ppb |
Next steps for Potosi, WI
Test your own tap with a certified lab first-draw sample; Potosi, 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 Potosi 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. The lead result guide covers how utilities pick the homes they sample. Systems that went over once often dip back under; here is what that means.