We read 17 results from Fond Du Lac Waterworks’s 2025 water quality report. No results over a legal limit; 5 above a health goal or guideline.
Serves about 44,303 people · Water system ID WI4200469 · Read the district’s 2025 report (opens in a new tab)
Open this district in the water lookupCompare with your own test results, see the district map and get matched filters.
Results from the 2025 report
Each number is copied from the district’s report and links to the page it’s printed on. Where the report lists several plants, wells or purchased water, the highest is shown.
| Contaminant | Result | Health goal | Legal limit | What it means |
|---|---|---|---|---|
| Arsenichighest measured · range ND to 3 · listed as a violation in the report · sampled 2023 · Wells · 2025 report, page 3 | 3 ppb | 0.004 ppb | 10 ppb | Above the health goal750x the health goal |
| Gross alpha (radioactivity)highest measured · range 3.3 to 6.8 · listed as a violation in the report · Wells · 2025 report, page 4 | 6.8 pCi/L | 0 pCi/L | 15 pCi/L | Above the health goalThe health goal is zero |
| Lead90th percentile of 60 homes tested, 0 over the action level · listed as a violation in the report · Customer taps · 2025 report, page 4 | 6.1 ppb | 0.2 ppb | 15 ppb (action level) | Above the health goal30x the health goal |
| Radium (combined 226 + 228)highest measured · range 1.4 to 2.4 · listed as a violation in the report · Wells · 2025 report, page 4 | 2.4 pCi/L | 0 pCi/L | 5 pCi/L | Above the health goalThe health goal is zero |
| Uraniumhighest measured · range 0.5 to 1 · listed as a violation in the report · Wells · 2025 report, page 4 | 1 ppb | 0.6 ppb | 30 ppb | Above the health goal1.7x the health goal |
| Bariumhighest measured · range 0.03 to 0.05 · listed as a violation in the report · sampled 2023 · Wells · 2025 report, page 4 | 0.05 ppm | 2 ppm | 2 ppm | Below the health goal |
| Chloridehighest measured · range 79 to 120 · sampled 2020 · Wells · 2025 report, page 4 | 120 ppm | — | 250 ppm guideline | Within the guideline |
| Copper90th percentile of 60 homes tested, 0 over the action level · listed as a violation in the report · Customer taps · 2025 report, page 4 | 0.29 ppm | 0.3 ppm | 1.3 ppm (action level) | Below the health goal |
| Disinfection byproducts (HAA5)highest running annual average · range 9 to 12 · listed as a violation in the report · Site D-2 · 2025 report, page 3 | 11 ppb | None set | 60 ppb | Below the legal limit |
| Disinfection byproducts (TTHM)highest running annual average · range 28.8 to 61 · listed as a violation in the report · Site D-51 · 2025 report, page 3 | 42 ppb | None set | 80 ppb | Below the legal limit |
| Fluoridehighest measured · range ND to 0.6 · listed as a violation in the report · sampled 2023 · Wells · 2025 report, page 4 | 0.6 ppm | 1 ppm | 4 ppm | Below the health goal |
| Nitrate (as N)highest measured · range ND to 0.08 · listed as a violation in the report · Wells · 2025 report, page 4 | 0.08 ppm | 10 ppm | 10 ppm | Below the health goal |
| Seleniumhighest measured · range ND to 3 · listed as a violation in the report · sampled 2023 · Wells · 2025 report, page 4 | 3 ppb | 30 ppb | 50 ppb | Below the health goal |
| Sulfatehighest measured · range 89 to 170 · sampled 2023 · Wells · 2025 report, page 5 | 170 ppm | — | 250 ppm guideline | Within the guideline |
| Lithiumhighest measured · range 12 to 20 · sampled 2023 · Wells · 2025 report, page 5 | 20 ppb | None set | None | No health limit |
| Nickelhighest measured · range 1.1 to 2.4 · listed as a violation in the report · sampled 2023 · Wells · 2025 report, page 4 | 2.4 ppb | None set | None | No health limit |
| Sodiumhighest measured · range 42 to 55 · listed as a violation in the report · sampled 2023 · Wells · 2025 report, page 4 | 55 ppm | None set | None | No health limit |
Utility results describe the whole system, measured where water enters the pipes, not your tap. Your home’s plumbing can add lead or copper.
EPA testing for PFAS and lithium
EPA’s own nationwide testing (UCMR 5) found these in Fond Du Lac Waterworks’s water between Mar 2023 and Oct 2023. These are EPA lab results, separate from the district’s report. Anything not listed was not detected.
- Lithium20 ppbFound in 8 of 8 samples · highest resultAbove EPA’s health reference level of 10 ppb (a guide, not a legal limit)
Source: EPA UCMR 5 occurrence data. The highest single result is shown; one high sample doesn’t mean every glass is that high.
What you can do
Nothing here is an emergency notice: if the district has a violation, it must tell customers directly. If you’d like to lower these at your tap, these are the treatments that remove them, and the catalog shows the models certified for each. Ranking is by certified removal; commissions never change the order.
Radium and uranium
Found: Gross alpha (radioactivity), Radium (combined 226 + 228), Uranium
What removes it: Reverse osmosis.
Lead
Found: Lead
What removes it: Certified carbon block or RO.
More districts: Wisconsin water quality · All states · Something look wrong? Tell us