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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 1 cities serving 876,036 residents
San Francisco County in California has an average water quality score of 86/100 (Grade A-) based on analysis of 1 municipal water systems. The county's water systems serve approximately 876,036 residents.
Overall, San Francisco County demonstrates good water quality standards. 1 of 1 cities exceed the county average, with San Francisco leading with a score of 86/100.
1 cities ranked by water quality score
| Rank | City | Score | Grade | Population |
|---|---|---|---|---|
| 1 | San Francisco Top concern: Total Trihalomethanes (41.8% of limit) | 86 | A- | 876,036 |
Top detected contaminants across county water systems
| Contaminant | Avg Level | Max Level | EPA Limit | % of Limit | Cities |
|---|---|---|---|---|---|
| Total Trihalomethanes | 33.451 ug/L | 33.451 ug/L | 80 ug/L | 41.8% | 1 |
| Mercury | 0.001 mg/L | 0.001 mg/L | 0.002 mg/L | 30% | 1 |
| Lead | 0.004 mg/L | 0.004 mg/L | 0.015 mg/L | 28.7% | 1 |
| Fluoride | 0.957 mg/L | 0.957 mg/L | 4 mg/L | 23.9% | 1 |
| Copper | 0.229 mg/L | 0.229 mg/L | 1.3 mg/L | 17.6% | 1 |
| Nitrite | 0.152 mg/L | 0.152 mg/L | 1 mg/L | 15.2% | 1 |
| Nitrate | 1.311 mg/L | 1.311 mg/L | 10 mg/L | 13.1% | 1 |
| Arsenic | 0.001 mg/L | 0.001 mg/L | 0.01 mg/L | 5% | 1 |
Water quality in San Francisco County, California reflects the region's unique combination of water sources, treatment infrastructure, and environmental factors. Our comprehensive analysis examines 1 municipal water systems serving a combined population of over 876,036 residents.
The county shows strong water quality performance, with scores ranging from 86/100 in San Francisco to 86/100 in San Francisco. This 0-point spread indicates relatively consistent water quality standards across municipal systems.
The most prevalent contaminants detected across San Francisco County water systems include Total Trihalomethanes, Mercury, Lead. All monitored contaminants remain within acceptable levels relative to EPA Maximum Contaminant Levels (MCLs).
San Francisco 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.
San Francisco County has an average water quality score of 86/100 (Grade A-) based on analysis of 1 municipal water systems serving 876,036 residents.
San Francisco has the highest water quality score in San Francisco County at 86/100. View the detailed report for San Francisco.
Most cities in San Francisco 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.