We read 12 results from Mokena’s 2025 water quality report. No results over a legal limit; 3 above a health goal or guideline.
Serves about 19,887 people · Water system ID IL1970600 · 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 ND to 0.54 · City of Chicago (source water) · 2025 report, page 4 | 0.54 ppb | 0.004 ppb | 10 ppb | Above the health goal135x the health goal |
| Gross alpha (radioactivity)highest measured · range 2.8 to 3.1 · sampled 2020 · City of Chicago (source water) · 2025 report, page 4 | 3.1 pCi/L | 0 pCi/L | 15 pCi/L | Above the health goalThe health goal is zero |
| Radium (combined 226 + 228)highest measured · range 0.83 to 0.95 · sampled 2020 · City of Chicago (source water) · 2025 report, page 4 | 0.95 pCi/L | 0 pCi/L | 5 pCi/L | Above the health goalThe health goal is zero |
| Bariumhighest measured · range 0.02 to 0.02 · City of Chicago (source water) · 2025 report, page 4 | 0.02 ppm | 2 ppm | 2 ppm | Below the health goal |
| Chlorinehighest measured · range 0.7 to 1.16 · 2025 report, page 3 | 0.9 ppm | None set | 4 ppm | Below the legal limit |
| Copper90th percentile of homes tested, 0 over the action level · Customer taps · 2025 report, page 3 | 0.06 ppm | 0.3 ppm | 1.3 ppm (action level) | Below the health goal |
| Disinfection byproducts (HAA5)highest measured · range 10.4 to 25 · 2025 report, page 3 | 19 ppb | None set | 60 ppb | Below the legal limit |
| Disinfection byproducts (TTHM)highest measured · range 22 to 53 · 2025 report, page 3 | 45 ppb | None set | 80 ppb | Below the legal limit |
| Fluoridehighest measured · range 0.65 to 0.75 · City of Chicago (source water) · 2025 report, page 4 | 0.75 ppm | 1 ppm | 4 ppm | Below the health goal |
| Nitrate (as N)highest measured · range 0.32 to 0.36 · City of Chicago (source water) · 2025 report, page 4 | 0.36 ppm | 10 ppm | 10 ppm | Below the health goal |
| Sulfatehighest measured · range 26.8 to 27.2 · City of Chicago (source water) · 2025 report, page 4 | 27.2 ppm | — | 250 ppm guideline | Within the guideline |
| Sodiumhighest measured · range 8.67 to 9.1 · City of Chicago (source water) · 2025 report, page 4 | 9.1 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.
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.
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