We read 24 results from St Peters Pws’s 2025 water quality report. No results over a legal limit; 2 above a health goal or guideline.
Serves about 52,575 people · Water system ID MO6010719 · 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 1.9 to 1.9 · sampled 2023 · highest of 2 sources · 2025 report, page 2 | 1.9 ppb | 0.004 ppb | 10 ppb | Above the health goal475x 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 0.03 to 0.03 · sampled 2023 · highest of 2 sources · 2025 report, page 2 | 0.03 ppm | 2 ppm | 2 ppm | Below the health goal |
| Chloridehighest measured · range 138 to 138 · sampled 2023 · 2025 report, page 3 | 138 ppm | — | 250 ppm guideline | Within the guideline |
| 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 | 0.01 ppm | 0.3 ppm | 1.3 ppm (action level) | Below the health goal |
| Disinfection byproducts (HAA5)highest running annual average · range 7 to 41 · DBPDUAL-04, highest of 5 sources · 2025 report, page 2 | 20 ppb | None set | 60 ppb | Below the legal limit |
| Disinfection byproducts (TTHM)highest running annual average · range 3.9 to 46.7 · DBPDUAL-04, highest of 5 sources · 2025 report, page 2 | 22 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 |
| Manganesehighest measured · range 0.02 to 0.02 · sampled 2023 · 2025 report, page 3 | 0.02 ppm | — | 0.05 ppm guideline | Within the guideline |
| 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 |
| pHhighest measured · range 8.15 to 8.15 · sampled 2023 · 2025 report, page 3 | 8.15 | — | — | Normal range |
| 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 |
| Sulfatehighest measured · range 65.6 to 65.6 · sampled 2023 · 2025 report, page 3 | 65.6 ppm | — | 250 ppm guideline | Within the guideline |
| Total dissolved solidshighest measured · range 482 to 482 · sampled 2023 · 2025 report, page 3 | 482 ppm | — | 500 ppm guideline | Within the guideline |
| Zinchighest measured · range 0.006 to 0.006 · sampled 2023 · 2025 report, page 3 | 0.006 ppm | — | 5 ppm guideline | Within the guideline |
| Alkalinityhighest measured · range 100 to 100 · sampled 2023 · 2025 report, page 3 | 100 ppm | None set | None | No health limit |
| Calciumhighest measured · range 27.8 to 27.8 · sampled 2023 · 2025 report, page 3 | 27.8 ppm | None set | None | No health limit |
| Hardnesshighest measured · range 10.1 to 10.1 · sampled 2023 · 2025 report, page 3 | 10.1 gpg (173 ppm) | — | — | Hard |
| Magnesiumhighest measured · range 25.2 to 25.2 · sampled 2023 · 2025 report, page 3 | 25.2 ppm | None set | None | No health limit |
| Potassiumhighest measured · range 2.94 to 2.94 · sampled 2023 · 2025 report, page 3 | 2.94 ppm | None set | None | No health limit |
| Sodiumhighest measured · range 75.3 to 75.3 · sampled 2023 · 2025 report, page 3 | 75.3 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. 11 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 Peters 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.
- PFOA4.9 pptFound in 2 of 6 samples · highest resultAbove the federal limit that takes effect in 2029 (4 ppt)
- Lithium53.1 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.
PFAS ("forever chemicals")
Found: PFOA (EPA testing)
What removes it: Reverse osmosis.
More districts: Missouri water quality · All states · Something look wrong? Tell us