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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 8 cities serving 1,656,777 residents
Santa Clara County in California has an average water quality score of 77/100 (Grade B) based on analysis of 8 municipal water systems. The county's water systems serve approximately 1,656,777 residents.
Water quality in Santa Clara County is fair, with some cities showing room for improvement. 2 cities have scores below 70, indicating elevated contaminant levels that residents should be aware of. Gilroy has the best water quality at 93/100.
8 cities ranked by water quality score
| Rank | City | Score | Grade | Population |
|---|---|---|---|---|
| 1 | Gilroy Top concern: Fluoride (18.6% of limit) | 93 | A | 58,916 |
| 2 | Milpitas Top concern: Lead (18.4% of limit) | 91 | A | 83,176 |
| 3 | Mountain View Top concern: Mercury (29.8% of limit) | 87 | A- | 84,853 |
| 4 | Palo Alto Top concern: Fluoride (15.9% of limit) | 87 | A- | 69,367 |
| 5 | Sunnyvale Top concern: Total Trihalomethanes (44.7% of limit) | 80 | B+ | 160,723 |
| 6 | Cupertino Top concern: Copper (31.8% of limit) | 79 | B | 62,118 |
| 7 | Santa Clara Top concern: Haloacetic Acids (64.4% of limit) | 52 | D | 125,268 |
| 8 | San Jose Top concern: Total Trihalomethanes (56% of limit) | 47 | F | 1,012,356 |
Top detected contaminants across county water systems
| Contaminant | Avg Level | Max Level | EPA Limit | % of Limit | Cities |
|---|---|---|---|---|---|
| Total Trihalomethanes | 24.071 ug/L | 44.821 ug/L | 80 ug/L | 30.1% | 7 |
| Lead | 0.004 mg/L | 0.007 mg/L | 0.015 mg/L | 25.4% | 8 |
| Fluoride | 0.876 mg/L | 1.212 mg/L | 4 mg/L | 21.9% | 5 |
| Nitrite | 0.206 mg/L | 0.417 mg/L | 1 mg/L | 20.6% | 8 |
| Haloacetic Acids | 11.977 ug/L | 38.655 ug/L | 60 ug/L | 20% | 7 |
| Arsenic | 0.002 mg/L | 0.004 mg/L | 0.01 mg/L | 17.7% | 7 |
| Mercury | 0 mg/L | 0.001 mg/L | 0.002 mg/L | 17.1% | 7 |
| Copper | 0.213 mg/L | 0.414 mg/L | 1.3 mg/L | 16.4% | 8 |
Recent violations across county water systems
Showing 10 of 20 recent violations
Water quality in Santa Clara County, California reflects the region's unique combination of water sources, treatment infrastructure, and environmental factors. Our comprehensive analysis examines 8 municipal water systems serving a combined population of over 1,656,777 residents.
The county shows moderate water quality performance, with scores ranging from 47/100 in San Jose to 93/100 in Gilroy. 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 Santa Clara County water systems include Total Trihalomethanes, Lead, Fluoride. All monitored contaminants remain within acceptable levels relative to EPA Maximum Contaminant Levels (MCLs).
Water quality in Santa Clara 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.
Santa Clara County has an average water quality score of 77/100 (Grade B) based on analysis of 8 municipal water systems serving 1,656,777 residents.
Gilroy has the highest water quality score in Santa Clara County at 93/100. View the detailed report for Gilroy.
Given the water quality variation across Santa Clara County, we recommend reviewing your specific city's water quality report. 2 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.