We read 13 results from St Charles’s 2025 water quality report. No results over a legal limit; 4 above a health goal or guideline.
Serves about 33,103 people · Water system ID IL0894830 · Read the district’s 2025 report (opens in a new tab)
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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 |
|---|---|---|---|---|
| Gross alpha (radioactivity)highest running annual average · range 8.32 to 11.6 · listed as a violation in the report · Wells · 2025 report, page 9 | 12 pCi/L | 0 pCi/L | 15 pCi/L | Above the health goalThe health goal is zero |
| Lead90th percentile of homes tested, 4 over the action level · listed as a violation in the report · Customer taps · 2025 report, page 8 | 7.5 ppb | 0.2 ppb | 15 ppb (action level) | Above the health goal38x the health goal |
| Manganesehighest measured · range ND to 0.09 · listed as a violation in the report · printed as 88 ppb · sampled 2024 · Wells · 2025 report, page 10 | 0.09 ppm | — | 0.05 ppm guideline | Above the guideline1.8x the guideline (taste, odor or stains; not a health limit) |
| Radium (combined 226 + 228)highest running annual average · range 1.73 to 5.44 · listed as a violation in the report · Wells · 2025 report, page 9 | 5 pCi/L | 0 pCi/L | 5 pCi/L | Above the health goalThe health goal is zero |
| Bariumhighest measured · range 0.07 to 0.58 · listed as a violation in the report · sampled 2024 · Wells · 2025 report, page 10 | 0.58 ppm | 2 ppm | 2 ppm | Below the health goal |
| Chlorinehighest measured · range 0.7 to 1.2 · listed as a violation in the report · Distribution system · 2025 report, page 9 | 1 ppm | None set | 4 ppm | Below the legal limit |
| cis-1,2-Dichloroethylenehighest measured · range 1.4 to 1.5 · listed as a violation in the report · Wells · 2025 report, page 9 | 1.5 ppb | 70 ppb | 70 ppb | Below the health goal |
| Copper90th percentile of homes tested, 0 over the action level · listed as a violation in the report · Customer taps · 2025 report, page 8 | 0.25 ppm | 0.3 ppm | 1.3 ppm (action level) | Below the health goal |
| Disinfection byproducts (HAA5)highest running annual average · range 1.18 to 7.97 · listed as a violation in the report · Distribution system · 2025 report, page 9 | 8 ppb | None set | 60 ppb | Below the legal limit |
| Disinfection byproducts (TTHM)highest running annual average · range 9.34 to 26.5 · listed as a violation in the report · Distribution system · 2025 report, page 9 | 26 ppb | None set | 80 ppb | Below the legal limit |
| Fluoridehighest measured · listed as a violation in the report · sampled 2024 · Wells · 2025 report, page 10 | 0.94 ppm | 1 ppm | 4 ppm | Below the health goal |
| Ironhighest measured · range ND to 0.2 · listed as a violation in the report · sampled 2024 · Wells · 2025 report, page 10 | 0.2 ppm | — | 0.3 ppm guideline | Within the guideline |
| Seleniumhighest measured · range ND to 1.2 · listed as a violation in the report · sampled 2024 · Wells · 2025 report, page 10 | 1.2 ppb | 30 ppb | 50 ppb | Below the health goal |
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 St Charles’s water between Jun 2024 and Feb 2026. These are EPA lab results, separate from the district’s report. Anything not listed was not detected.
- PFBS6.2 pptFound in 3 of 10 samples · highest resultNo federal limit in force for this one
- Lithium28.6 ppbFound in 6 of 10 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)
What removes it: Reverse osmosis.
Lead
Found: Lead
What removes it: Certified carbon block or RO.
Sediment or cloudy water
Found: Manganese
What removes it: Oxidation filter.
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