We read 10 results from Lake Zurich’s 2025 water quality report. No results over a legal limit; 1 above a health goal or guideline.
Serves about 19,759 people · Water system ID IL0970850 · 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 0.07 · 2025 report, page 6 | 0.07 ppb | 0.004 ppb | 10 ppb | Above the health goal18x the health goal |
| Chlorinehighest running annual average · range 0.9 to 1.3 · 2025 report, page 5 | 1.1 ppm | None set | 4 ppm | Below the legal limit |
| Chromium (total)highest measured · range ND to 1.04 · 2025 report, page 6 | 1.04 ppb | None set | 100 ppb | Below the legal limit |
| Copper90th percentile of homes tested, 0 over the action level · Customer taps · 2025 report, page 5 | 0.14 ppm | 0.3 ppm | 1.3 ppm (action level) | Below the health goal |
| Disinfection byproducts (HAA5)highest running annual average · range 0.89 to 2.3 · 2025 report, page 5 | 2 ppb | None set | 60 ppb | Below the legal limit |
| Disinfection byproducts (TTHM)highest running annual average · range 7.1 to 10 · 2025 report, page 5 | 10 ppb | None set | 80 ppb | Below the legal limit |
| Fluoridehighest measured · range 0.94 to 0.94 · sampled 2024 · 2025 report, page 6 | 0.94 ppm | 1 ppm | 4 ppm | Below the health goal |
| Seleniumhighest measured · range 0.11 to 0.23 · 2025 report, page 6 | 0.23 ppb | 30 ppb | 50 ppb | Below the health goal |
| Zinchighest measured · range 0.0014 to 0.0033 · 2025 report, page 6 | 0.0033 ppm | — | 5 ppm guideline | Within the guideline |
| Sodiumhighest measured · range 91.6 to 123 · printed as 123000 ppb · sampled 2024 · 2025 report, page 6 | 123 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. 3 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 Lake Zurich’s water between Jun 2023 and Sep 2024. These are EPA lab results, separate from the district’s report. Anything not listed was not detected.
- Lithium26 ppbFound in 8 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.
More districts: Illinois water quality · All states · Something look wrong? Tell us