We read 19 results from Mesa Water District’s 2025 water quality report. No results over a legal limit; 4 above a health goal or guideline.
Serves about 110,000 people · Water system ID CA3010004 · 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 3.2 · Groundwater · 2025 report, page 6 | 3.2 ppb | 0.004 ppb | 10 ppb | Above the health goal800x the health goal |
| Chromium-6average · range ND to 0.8 · Groundwater · 2025 report, page 6 | 0.34 ppb | 0.02 ppb | 10 ppb | Above the health goal17x the health goal |
| Gross alpha (radioactivity)highest measured · range ND to 3.77 · Groundwater · 2025 report, page 6 | 3.77 pCi/L | 0 pCi/L | 15 pCi/L | Above the health goalThe health goal is zero |
| Uraniumhighest measured · range ND to 4.22 · printed as 2.83 pCi/L · Groundwater · 2025 report, page 6 | 4.22 ppb | 0.6 ppb | 30 ppb | Above the health goal7x the health goal |
| Chlorideaverage · range 12.8 to 176 · Groundwater · 2025 report, page 6 | 56.5 ppm | — | 250 ppm guideline | Within the guideline |
| Chlorineaverage · range 0.19 to 2.78 · Distribution system · 2025 report, page 6 | 2.07 ppm | None set | 4 ppm | Below the legal limit |
| Copper90th percentile of 50 homes tested, 0 over the action level · sampled 2023 · Customer taps · 2025 report, page 6 | 0.09 ppm | 0.3 ppm | 1.3 ppm (action level) | Below the health goal |
| Disinfection byproducts (HAA5)average · range ND to 20 · Distribution system · 2025 report, page 6 | 7 ppb | None set | 60 ppb | Below the legal limit |
| Disinfection byproducts (TTHM)average · range ND to 34 · Distribution system · 2025 report, page 6 | 15 ppb | None set | 80 ppb | Below the legal limit |
| Fluorideaverage · range 0.26 to 0.76 · Groundwater · 2025 report, page 6 | 0.46 ppm | 1 ppm | 2 ppm | Below the health goal |
| Lead90th percentile of 50 homes tested, 1 over the action level · sampled 2023 · Customer taps · 2025 report, page 6 | Not detected | 0.2 ppb | 15 ppb (action level) | Not detected |
| Nitrate (as N)average · range ND to 1.43 · Groundwater · 2025 report, page 6 | 0.39 ppm | 10 ppm | 10 ppm | Below the health goal |
| Sulfateaverage · range 1.4 to 155 · Groundwater · 2025 report, page 6 | 45 ppm | — | 250 ppm guideline | Within the guideline |
| Total dissolved solidsaverage · range 150 to 582 · Groundwater · 2025 report, page 6 | 327 ppm | — | 500 ppm guideline | Within the guideline |
| 1,4-Dioxanehighest measured · range ND to 2.5 · Groundwater · 2025 report, page 6 | 2.5 ppb | None set | None | No health limit |
| Conductivityaverage · range 239 to 872 · Groundwater · 2025 report, page 6 | 529 µS/cm | None set | None | No health limit |
| Hardnessaverage · range 1.21 to 17.1 · Groundwater · 2025 report, page 6 | 6.61 gpg (113 ppm) | — | — | Moderately hard |
| Sodiumaverage · range 23 to 184 · Groundwater · 2025 report, page 6 | 72.7 ppm | None set | None | No health limit |
| Vanadiumaverage · range ND to 6.7 · Groundwater · 2025 report, page 6 | 4.5 ppb | 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.
EPA testing for PFAS and lithium
EPA’s own nationwide testing (UCMR 5) found these in Mesa Water District’s water between Mar 2023 and Aug 2024. These are EPA lab results, separate from the district’s report. Anything not listed was not detected.
- Lithium37.3 ppbFound in 3 of 20 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), Uranium
What removes it: Reverse osmosis.
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