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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 10 cities serving 1,453,079 residents
Alameda County in California has an average water quality score of 76/100 (Grade B) based on analysis of 10 municipal water systems. The county's water systems serve approximately 1,453,079 residents.
Water quality in Alameda County is fair, with some cities showing room for improvement. 3 cities have scores below 70, indicating elevated contaminant levels that residents should be aware of. Hayward has the best water quality at 90/100.
10 cities ranked by water quality score
| Rank | City | Score | Grade | Population |
|---|---|---|---|---|
| 1 | Hayward Top concern: Fluoride (14.7% of limit) | 90 | A | 164,384 |
| 2 | Union City Top concern: Fluoride (16% of limit) | 89 | A- | 74,721 |
| 3 | Fremont Top concern: Total Trihalomethanes (15.4% of limit) | 87 | A- | 230,120 |
| 4 | Livermore Top concern: Nitrate (29.2% of limit) | 85 | A- | 91,223 |
| 5 | Dublin Top concern: Arsenic (26.2% of limit) | 85 | A- | 73,910 |
| 6 | Berkeley Top concern: Total Trihalomethanes (34.8% of limit) | 73 | B- | 122,409 |
| 7 | San Leandro Top concern: Copper (34.3% of limit) | 72 | B- | 90,105 |
| 8 | Oakland Top concern: Total Trihalomethanes (34.4% of limit) | 68 | C+ | 438,366 |
| 9 | Pleasanton Top concern: Lead (63.7% of limit) | 68 | C+ | 83,447 |
| 10 | Alameda Top concern: Lead (52.3% of limit) | 44 | F | 84,394 |
Top detected contaminants across county water systems
| Contaminant | Avg Level | Max Level | EPA Limit | % of Limit | Cities |
|---|---|---|---|---|---|
| Lead | 0.004 mg/L | 0.01 mg/L | 0.015 mg/L | 24.7% | 9 |
| Total Trihalomethanes | 19.319 ug/L | 40.374 ug/L | 80 ug/L | 24.1% | 9 |
| Arsenic | 0.002 mg/L | 0.005 mg/L | 0.01 mg/L | 20% | 9 |
| Fluoride | 0.773 mg/L | 1.082 mg/L | 4 mg/L | 19.3% | 9 |
| Mercury | 0 mg/L | 0.001 mg/L | 0.002 mg/L | 19.2% | 6 |
| Haloacetic Acids | 10.744 ug/L | 25.55 ug/L | 60 ug/L | 17.9% | 8 |
| Copper | 0.224 mg/L | 0.473 mg/L | 1.3 mg/L | 17.3% | 9 |
| Nitrate | 1.557 mg/L | 3.041 mg/L | 10 mg/L | 15.6% | 10 |
Recent violations across county water systems
Showing 10 of 20 recent violations
Water quality in Alameda County, California reflects the region's unique combination of water sources, treatment infrastructure, and environmental factors. Our comprehensive analysis examines 10 municipal water systems serving a combined population of over 1,453,079 residents.
The county shows moderate water quality performance, with scores ranging from 44/100 in Alameda to 90/100 in Hayward. This 46-point spread indicates significant variation in water quality across the county, suggesting different water sources or treatment approaches.
The most prevalent contaminants detected across Alameda County water systems include Lead, Total Trihalomethanes, Arsenic. All monitored contaminants remain within acceptable levels relative to EPA Maximum Contaminant Levels (MCLs).
Water quality in Alameda 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.
Alameda County has an average water quality score of 76/100 (Grade B) based on analysis of 10 municipal water systems serving 1,453,079 residents.
Hayward has the highest water quality score in Alameda County at 90/100. View the detailed report for Hayward.
Given the water quality variation across Alameda County, we recommend reviewing your specific city's water quality report. 3 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.