We read 12 results from Lago del Oro Water Company’s 2023 water quality report. No results over a legal limit; 4 above a health goal or guideline.
Serves about 18,132 people · Water system ID AZ0411117 · Read the district’s 2023 report (opens in a new tab)
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Results from the 2023 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 · 2023 report, page 3 | 2.5 ppb | 0.004 ppb | 10 ppb | Above the health goal625x the health goal |
| Gross alpha (radioactivity)highest measured · sampled 2021 · 2023 report, page 2 | 8.1 pCi/L | 0 pCi/L | 15 pCi/L | Above the health goalThe health goal is zero |
| Radium (combined 226 + 228)highest measured · sampled 2021 · 2023 report, page 2 | 1.1 pCi/L | 0 pCi/L | 5 pCi/L | Above the health goalThe health goal is zero |
| Uraniumhighest measured · range 1.3 to 10.4 · sampled 2021 · 2023 report, page 2 | 10.4 ppb | 0.6 ppb | 30 ppb | Above the health goal17x the health goal |
| Bariumhighest measured · 2023 report, page 3 | 0.06 ppm | 2 ppm | 2 ppm | Below the health goal |
| Chlorinehighest measured · range 0.87 to 0.97 · 2023 report, page 3 | 0.97 ppm | None set | 4 ppm | Below the legal limit |
| Copper90th percentile of homes tested · sampled 2021 · Customer taps · 2023 report, page 3 | 0.29 ppm | 0.3 ppm | 1.3 ppm (action level) | Below the health goal |
| Disinfection byproducts (HAA5)highest measured · 2023 report, page 3 | 2.2 ppb | None set | 60 ppb | Below the legal limit |
| Disinfection byproducts (TTHM)highest measured · range 11.1 to 13.4 · 2023 report, page 3 | 13.4 ppb | None set | 80 ppb | Below the legal limit |
| Fluoridehighest measured · 2023 report, page 3 | 0.58 ppm | 1 ppm | 4 ppm | Below the health goal |
| Lead90th percentile of homes tested · sampled 2021 · Customer taps · 2023 report, page 3 | Not detected | 0.2 ppb | 15 ppb (action level) | Not detected |
| Nitrate (as N)highest measured · range 0.43 to 3.99 · 2023 report, page 3 | 3.99 ppm | 10 ppm | 10 ppm | 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 Lago del Oro Water Company’s water between Oct 2024 and Apr 2026. These are EPA lab results, separate from the district’s report. Anything not listed was not detected.
- Lithium20 ppbFound in 13 of 26 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), Uranium
What removes it: Reverse osmosis.
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