Fond Du Lac Waterworks, WI
Lead detected, under the action levels
Latest 90th-percentile lead: 6.1 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
Fond Du Lac Waterworks serves about 44,678 people through 16,049 service connections, which makes it a large system under EPA's size classes. It is owned by a local government (city, town, county or district) and draws groundwater, in Fond Du Lac County, Wisconsin. EPA system ID: WI4200469. Ask the utility on your bill for your address in their service line inventory.
Every lead result on file
That is down 1.8 ppb from 7.9 ppb in the period ending 2025. The highest 90th-percentile result EPA holds for Fond Du Lac Waterworks is 15 ppb across 11 monitoring periods, none of them over 15 ppb (4 over 10 ppb).
| Period ending | 90th-percentile lead |
|---|---|
| 2025 | 6.1 ppb |
| 2025 | 7.9 ppb |
| 2021 | 9.5 ppb |
| 2020 | 8.5 ppb |
| 2019 | 10 ppb |
| 2019 | 10 ppb |
| 2018 | 12 ppb over 10 |
| 2018 | 10 ppb |
| 2017 | 15 ppb over 10 |
| 2017 | 11 ppb over 10 |
| 2016 | 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. Fond Du Lac Waterworks's 6.1 ppb sits at the 91st percentile in Wisconsin and the 94th nationally (higher means more lead).
Neighbouring systems
14 other systems share Fond Du Lac County; 3 of them have a higher latest lead result than Fond Du Lac Waterworks. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Ripon Water Utility | 7,716 | 3.5 ppb |
| North Fond Du Lac Waterworks | 5,414 | 9.1 ppb |
| Campbellsport Waterworks | 1,825 | 1.12 ppb |
| Oakfield Waterworks | 1,058 | 0 (not detected) |
| Ashwood Grove Edgewater | 1,046 | 2.4 ppb |
| Fond Du Lac Tn Water Utility | 980 | 3.6 ppb |
| Brandon Waterworks | 872 | 6.86 ppb |
| Mount Calvary Waterworks | 478 | 0.45 ppb |
| St Cloud Waterworks | 471 | 1.9 ppb |
| Fairwater Waterworks | 365 | 1.75 ppb |
Your move
Test your own tap with a certified lab first-draw sample; Fond Du Lac, 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 Fond Du Lac 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.