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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 16 cities serving 4,049,097 residents
Maricopa County in Arizona has an average water quality score of 73/100 (Grade B-) based on analysis of 16 municipal water systems. The county's water systems serve approximately 4,049,097 residents.
Water quality in Maricopa County is fair, with some cities showing room for improvement. 6 cities have scores below 70, indicating elevated contaminant levels that residents should be aware of. Chandler has the best water quality at 95/100.
16 cities ranked by water quality score
| Rank | City | Score | Grade | Population |
|---|---|---|---|---|
| 1 | Chandler Top concern: Lead (18.5% of limit) | 95 | A+ | 271,393 |
| 2 | Tempe Top concern: Fluoride (19.1% of limit) | 86 | A- | 176,407 |
| 3 | Peoria Top concern: Total Trihalomethanes (22% of limit) | 85 | A- | 188,328 |
| 4 | Glendale Top concern: Lead (17.4% of limit) | 84 | B+ | 243,756 |
| 5 | Fountain Hills Top concern: Fluoride (18% of limit) | 84 | B+ | 26,048 |
| 6 | Gilbert Top concern: Total Trihalomethanes (40% of limit) | 83 | B+ | 270,016 |
| 7 | Buckeye Top concern: Nitrate (29.6% of limit) | 79 | B | 90,464 |
| 8 | Phoenix Top concern: Haloacetic Acids (30.8% of limit) | 70 | B- | 1,608,616 |
| 9 | Avondale Top concern: Fluoride (24.5% of limit) | 70 | B- | 88,840 |
| 10 | Queen Creek Top concern: Haloacetic Acids (38.3% of limit) | 70 | B- | 58,227 |
| 11 | Mesa Top concern: Haloacetic Acids (29.7% of limit) | 69 | C+ | 502,348 |
| 12 | Surprise Top concern: Haloacetic Acids (30.9% of limit) | 69 | C+ | 140,927 |
| 13 | Goodyear Top concern: Copper (48.1% of limit) | 66 | C+ | 88,803 |
| 14 | Paradise Valley Top concern: Lead (55.6% of limit) | 56 | C- | 17,473 |
| 15 | El Mirage Top concern: Total Trihalomethanes (64.6% of limit) | 55 | C- | 32,910 |
| 16 | Scottsdale Top concern: Haloacetic Acids (55.5% of limit) | 52 | D | 244,541 |
Top detected contaminants across county water systems
| Contaminant | Avg Level | Max Level | EPA Limit | % of Limit | Cities |
|---|---|---|---|---|---|
| Haloacetic Acids | 16.449 ug/L | 33.303 ug/L | 60 ug/L | 27.4% | 14 |
| Total Trihalomethanes | 20.647 ug/L | 51.673 ug/L | 80 ug/L | 25.8% | 14 |
| Lead | 0.003 mg/L | 0.008 mg/L | 0.015 mg/L | 22.8% | 14 |
| Fluoride | 0.904 mg/L | 1.436 mg/L | 4 mg/L | 22.6% | 16 |
| Copper | 0.29 mg/L | 0.709 mg/L | 1.3 mg/L | 22.3% | 15 |
| Chromium | 0.019 mg/L | 0.042 mg/L | 0.1 mg/L | 19.4% | 13 |
| Nitrate | 1.93 mg/L | 4.214 mg/L | 10 mg/L | 19.3% | 13 |
| Nitrite | 0.19 mg/L | 0.423 mg/L | 1 mg/L | 19% | 14 |
Recent violations across county water systems
Showing 10 of 20 recent violations
Water quality in Maricopa County, Arizona reflects the region's unique combination of water sources, treatment infrastructure, and environmental factors. Our comprehensive analysis examines 16 municipal water systems serving a combined population of over 4,049,097 residents.
The county shows moderate water quality performance, with scores ranging from 52/100 in Scottsdale to 95/100 in Chandler. This 43-point spread indicates significant variation in water quality across the county, suggesting different water sources or treatment approaches.
The most prevalent contaminants detected across Maricopa County water systems include Haloacetic Acids, Total Trihalomethanes, Lead. All monitored contaminants remain within acceptable levels relative to EPA Maximum Contaminant Levels (MCLs).
Water quality in Maricopa County is fair but shows room for improvement. Residents in cities scoring below 70 should consider water filtration, particularly for drinking and cooking. Check your specific city's report above for personalized recommendations.
Maricopa County has an average water quality score of 73/100 (Grade B-) based on analysis of 16 municipal water systems serving 4,049,097 residents.
Chandler has the highest water quality score in Maricopa County at 95/100. View the detailed report for Chandler.
Given the water quality variation across Maricopa County, we recommend reviewing your specific city's water quality report. 6 cities have scores below 70, where filtration is particularly recommended.
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.