Gilbert Water Quality Summary
Gilbert, Town Of supplies drinking water to about 247,600 people in Gilbert, Arizona, and draws from surface water (rivers, lakes, or reservoirs), which requires fuller treatment for runoff, sediment, and microbial risk. On the IsWaterSafe scale it earns a failing Water Safety Score of 33 out of 100 (Grade F), a composite of its EPA SDWIS violation and contaminant record.
EPA records show 3 health-based violations for this system plus 5 monitoring violations. A health-based violation means a contaminant exceeded its legal EPA limit, the most serious category in the Safe Drinking Water Act. The system has 101 enforcement actions on file in response.
Among the 20 substances sampled, Total Trihalomethanes is the clearest concern: a reading of 0.082 mg/l against an EPA limit (MCL) of 80 ppb, about 102% of the legal ceiling, sampled April 2017. In total, 2 contaminant exceedances are recorded for this system.
The most recent documented episode is a health-based violation involving Nitrate, beginning July 2018 and marked resolved January 2019.
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Detected Contaminants
| Contaminant | Detected Level | MCL (Limit) | Status | Sample Date |
|---|---|---|---|---|
| Total Trihalomethanes | 0.082 mg/l | 80 mg/l | Exceeds Limit | Apr 1, 2017 |
| Nitrate | 5 ppm | 10 ppm | Within Limit | Jan 1, 2017 |
| Haloacetic Acids (HAA5) | 30 ppb | 60 ppb | Within Limit | May 1, 2018 |
| Arsenic | 5 ppb | 10 ppb | Within Limit | Jul 1, 2020 |
| Chlorine | 2 ppm | 4 ppm | Within Limit | Jun 1, 2021 |
| Gross Alpha | 7.5 pCi/L | 15 pCi/L | Within Limit | Jan 1, 2019 |
| Uranium | 15 ppb | 30 ppb | Within Limit | Jan 1, 2019 |
| Gross Beta | 25 pCi/L | 50 pCi/L | Within Limit | Jan 1, 2019 |
| Barium | 1000 ppb | 2000 ppb | Within Limit | Jan 1, 2021 |
| Cadmium | 2.5 ppb | 5 ppb | Within Limit | Jan 1, 2021 |
| Chromium | 50 ppb | 100 ppb | Within Limit | Jan 1, 2021 |
| Cyanide | 100 ppb | 200 ppb | Within Limit | Jan 1, 2021 |
| Fluoride | 2000 ppb | 4000 ppb | Within Limit | Jan 1, 2021 |
| Mercury | 1 ppb | 2 ppb | Within Limit | Jan 1, 2021 |
| Antimony | 3 ppb | 6 ppb | Within Limit | Jan 1, 2021 |
| Beryllium | 2 ppb | 4 ppb | Within Limit | Jan 1, 2021 |
| Thallium | 1 ppb | 2 ppb | Within Limit | Jan 1, 2021 |
| Selenium | 25 ppb | 50 ppb | Within Limit | Jan 1, 2021 |
| Trichloroethylene | 2.5 ppb | 5 ppb | Within Limit | Jan 1, 2021 |
| PFOS/PFOA (PFAS) | 2 ppt | 4 ppt | Within Limit | Jan 1, 2021 |
Violation History
Frequently Asked Questions
Gilbert, Town Of has a Water Safety Score of F (33/100). The system serves 247,600 people and has 3 health violations on record. Check the contaminant table above for specific detected substances.
Gilbert, Town Of has 2 contaminant exceedances above EPA health guidelines. See the full contaminant detection table above for all tested substances and their levels relative to legal limits and health guidelines.
The Water Safety Score (0-100, grades A through F) is based on contaminant levels relative to legal limits, health guideline exceedances, violation history, and enforcement actions. Higher scores indicate fewer concerns.
If your water system has violations, request the Consumer Confidence Report from your utility, consider getting an independent water test from a certified lab, and look into certified water filters for specific contaminants of concern. For lead, run cold water for 30 seconds before drinking.
Water quality data sourced from EPA's Safe Drinking Water Information System (SDWIS). Safety scores are calculated based on contaminant levels, violations, and enforcement history. This is not a substitute for your utility's official Consumer Confidence Report.
Source: EPA Ground Water and Drinking Water, 2026.