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Not health advice. Contact your local water utility for concerns.
Data from EPA Water Quality Reports. For official information, contact your water utility or health department.
Water quality data for 3 cities serving 766,246 residents
Pima County in Arizona has an average water quality score of 86/100 (Grade B) based on analysis of 3 municipal water systems. The county's water systems serve approximately 766,246 residents.
Overall, Pima County demonstrates good water quality standards. 2 of 3 cities exceed the county average, with Sahuarita leading with a score of 98/100.
3 cities ranked by water quality score
| Rank | City | Score | Grade | Population |
|---|---|---|---|---|
| 1 | Sahuarita Biggest deduction: Arsenic: average 8.191 ug/l in 2012–2019 finished water, above 80% of the 10 ug/l MCL (−2 pts) | 98 | A | 18,178 |
| 2 | Tucson Biggest deduction: 32 monitoring/reporting violations in the last 5 years (−10 pts) | 88 | B | 732,906 |
| 3 | Marana Biggest deduction: PFOA detected at up to 6.3 ppt in UCMR5 sampling (2025-08-05), at or above EPA's 4 ppt MCL (−10 pts) | 73 | C | 15,162 |
Real EPA readings across county water systems (lead: latest 90th percentile; PFAS: UCMR5 2023–2026; others: 2012–2019 averages)
| Contaminant | Avg Level | Max Level | EPA Limit | % of Limit | Cities |
|---|---|---|---|---|---|
| PFAS (PFOA/PFOS max, UCMR5) | 5.967 ppt | 17.9 ppt | 4 ppt | 149.2% | 3 |
| Arsenic (2012–2019 avg) | 4.022 ug/L | 8.191 ug/L | 10 ug/L | 40.2% | 3 |
| Nitrate (2012–2019 avg) | 1.982 mg/L | 2.656 mg/L | 10 mg/L | 19.8% | 3 |
| Fluoride (2012–2019 avg) | 0.509 mg/L | 0.783 mg/L | 4 mg/L | 12.7% | 3 |
| Uranium (2012–2019 avg) | 2.826 ug/L | 2.952 ug/L | 30 ug/L | 9.4% | 2 |
| TTHM (2012–2019 avg) | 6.358 ug/L | 10.954 ug/L | 80 ug/L | 7.9% | 3 |
| Lead (90th percentile) | 0.216 ppb | 0.649 ppb | 15 ppb | 1.4% | 3 |
| HAA5 (2012–2019 avg) | 0.512 ug/L | 1.104 ug/L | 60 ug/L | 0.9% | 3 |
Recent violations across county water systems
Showing 10 of 20 recent violations
Water quality in Pima County, Arizona reflects the region's unique combination of water sources, treatment infrastructure, and environmental factors. Our comprehensive analysis examines 3 municipal water systems serving a combined population of over 766,246 residents.
The county shows strong water quality performance, with scores ranging from 73/100 in Marana to 98/100 in Sahuarita. This 25-point spread indicates significant variation in water quality across the county, suggesting different water sources or treatment approaches.
The most prevalent contaminants detected across Pima County water systems include PFAS (PFOA/PFOS max, UCMR5), Arsenic (2012–2019 avg), Nitrate (2012–2019 avg). At least one reading averages above 50% of its EPA limit across the county's systems, worth attention from residents and utilities.
Pima County's water quality is generally good. Residents can feel confident in their tap water quality, though those with specific health concerns or sensitivity to certain contaminants may still benefit from filtration. Regular review of your city's annual Consumer Confidence Report is recommended.
Pima County has an average water quality score of 86/100 (Grade B) based on analysis of 3 municipal water systems serving 766,246 residents.
Sahuarita has the highest water quality score in Pima County at 98/100. View the detailed report for Sahuarita.
Most cities in Pima County have water that meets EPA standards. However, a water filter can provide additional protection and improve taste. The need depends on your specific city and any personal health considerations.
Click on any city in the rankings table above to view its detailed water quality report, including contaminant levels, EPA compliance history, and filter recommendations.