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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 4 cities serving 572,735 residents
San Joaquin County in California has an average water quality score of 84/100 (Grade B+) based on analysis of 4 municipal water systems. The county's water systems serve approximately 572,735 residents.
Overall, San Joaquin County demonstrates good water quality standards. 2 of 4 cities exceed the county average, with Lodi leading with a score of 96/100.
4 cities ranked by water quality score
Top detected contaminants across county water systems
| Contaminant | Avg Level | Max Level | EPA Limit | % of Limit | Cities |
|---|---|---|---|---|---|
| Lead | 0.004 mg/L | 0.006 mg/L | 0.015 mg/L | 25.3% | 4 |
| Haloacetic Acids | 13.606 ug/L | 44.184 ug/L | 60 ug/L | 22.7% | 4 |
| Total Trihalomethanes | 18.016 ug/L | 45.711 ug/L | 80 ug/L | 22.5% | 4 |
| Fluoride | 0.807 mg/L | 1.092 mg/L | 4 mg/L | 20.2% | 4 |
| Arsenic | 0.002 mg/L | 0.005 mg/L | 0.01 mg/L | 19.5% | 4 |
| Nitrite | 0.194 mg/L | 0.414 mg/L | 1 mg/L | 19.4% | 4 |
| Mercury | 0 mg/L | 0.001 mg/L | 0.002 mg/L | 18.3% | 3 |
| Copper | 0.206 mg/L | 0.43 mg/L | 1.3 mg/L | 15.9% | 4 |
Recent violations across county water systems
Water quality in San Joaquin County, California reflects the region's unique combination of water sources, treatment infrastructure, and environmental factors. Our comprehensive analysis examines 4 municipal water systems serving a combined population of over 572,735 residents.
The county shows strong water quality performance, with scores ranging from 71/100 in Manteca to 96/100 in Lodi. 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 San Joaquin County water systems include Lead, Haloacetic Acids, Total Trihalomethanes. All monitored contaminants remain within acceptable levels relative to EPA Maximum Contaminant Levels (MCLs).
San Joaquin 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 Joaquin County has an average water quality score of 84/100 (Grade B+) based on analysis of 4 municipal water systems serving 572,735 residents.
Lodi has the highest water quality score in San Joaquin County at 96/100. View the detailed report for Lodi.
Most cities in San Joaquin 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.