We read 12 results from St Charles Pws’s 2025 water quality report. No results over a legal limit; 2 above a health goal or guideline.
Serves about 73,040 people · Water system ID MO6010707 · 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 |
|---|---|---|---|---|
| Arsenichighest measured · range 0.41 to 0.42 · Purchased water (wholesaler) · 2025 report, page 3 | 0.42 ppb | 0.004 ppb | 10 ppb | Above the health goal105x the health goal |
| Atrazinehighest measured · range ND to 0.96 · Purchased water (wholesaler) · 2025 report, page 3 | 0.96 ppb | 0.15 ppb | 3 ppb | Above the health goal6.4x the health goal |
| Antimonyhighest measured · range 0.27 to 0.28 · Purchased water (wholesaler) · 2025 report, page 3 | 0.28 ppb | 1 ppb | 6 ppb | Below the health goal |
| Bariumhighest measured · range 0.1 to 0.1 · sampled 2023 · highest of 2 sources · 2025 report, page 2 | 0.1 ppm | 2 ppm | 2 ppm | Below the health goal |
| Chromium (total)highest measured · range 1 to 1.11 · Purchased water (wholesaler) · 2025 report, page 3 | 1.11 ppb | None set | 100 ppb | Below the legal limit |
| Copper90th percentile of homes tested, 0 over the action level · sampled 2024 · Customer taps · 2025 report, page 2 | 0.0079 ppm | 0.3 ppm | 1.3 ppm (action level) | Below the health goal |
| Disinfection byproducts (HAA5)highest running annual average · range 6.4 to 22.3 · Purchased water: Distribution system, highest of 5 sources · 2025 report, page 3 | 20 ppb | None set | 60 ppb | Below the legal limit |
| Disinfection byproducts (TTHM)highest running annual average · range 4.1 to 17.7 · Purchased water: Distribution system, highest of 5 sources · 2025 report, page 3 | 20 ppb | None set | 80 ppb | Below the legal limit |
| Fluoridehighest measured · range 0.29 to 0.95 · Purchased water (wholesaler), highest of 2 sources · 2025 report, page 3 | 0.95 ppm | 1 ppm | 4 ppm | Below the health goal |
| Lead90th percentile of homes tested, 0 over the action level · sampled 2024 · Customer taps · 2025 report, page 2 | Not detected | 0.2 ppb | 15 ppb (action level) | Not detected |
| Nitrate (as N)highest measured · range 0.56 to 0.58 · Purchased water (wholesaler), highest of 2 sources · 2025 report, page 3 | 0.58 ppm | 10 ppm | 10 ppm | Below the health goal |
| Seleniumhighest measured · range 1.16 to 1.31 · Purchased water (wholesaler) · 2025 report, page 3 | 1.31 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. 24 numbers we weren’t sure about are held back until a person checks.
EPA testing for PFAS and lithium
EPA’s own nationwide testing (UCMR 5) found these in St Charles Pws’s water between Mar 2024 and Dec 2024. These are EPA lab results, separate from the district’s report. Anything not listed was not detected.
- Lithium45.1 ppbFound in 6 of 6 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.
Industrial chemicals and pesticides
Found: Atrazine
What removes it: Carbon block or RO.
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