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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 15 cities serving 1,703,202 residents
San Bernardino County in California has an average water quality score of 82/100 (Grade B+) based on analysis of 15 municipal water systems. The county's water systems serve approximately 1,703,202 residents.
Overall, San Bernardino County demonstrates good water quality standards. 10 of 15 cities exceed the county average, with Rialto leading with a score of 93/100.
15 cities ranked by water quality score
| Rank | City | Score | Grade | Population |
|---|---|---|---|---|
| 1 | Rialto Top concern: Fluoride (19.1% of limit) | 93 | A | 107,884 |
| 2 | Hesperia Top concern: Total Trihalomethanes (20.2% of limit) | 93 | A | 104,065 |
| 3 | Chino Top concern: Total Trihalomethanes (19.5% of limit) | 91 | A | 94,336 |
| 4 | Highland Top concern: Total Trihalomethanes (21% of limit) | 88 | A- | 57,463 |
| 5 | Rancho Cucamonga Top concern: Lead (17.2% of limit) | 87 | A- | 181,539 |
| 6 | Chino Hills Top concern: Fluoride (17.1% of limit) | 87 | A- | 83,011 |
| 7 | Colton Top concern: Total Trihalomethanes (21.1% of limit) | 87 | A- | 51,120 |
| 8 | Upland Top concern: Fluoride (15.3% of limit) | 85 | A- | 74,903 |
| 9 | Yucaipa Top concern: Lead (33.9% of limit) | 85 | A- | 56,602 |
| 10 | Apple Valley Top concern: Fluoride (19.2% of limit) | 83 | B+ | 75,979 |
| 11 | Fontana Top concern: Haloacetic Acids (41.2% of limit) | 81 | B+ | 215,674 |
| 12 | Ontario Top concern: Copper (29.4% of limit) | 81 | B+ | 176,890 |
| 13 | Victorville Top concern: Total Trihalomethanes (34.2% of limit) | 79 | B | 134,510 |
| 14 | Redlands Top concern: Total Trihalomethanes (72.5% of limit) | 63 | C | 68,132 |
| 15 | San Bernardino Top concern: Copper (54.1% of limit) | 45 | F | 221,094 |
Top detected contaminants across county water systems
| Contaminant | Avg Level | Max Level | EPA Limit | % of Limit | Cities |
|---|---|---|---|---|---|
| Total Trihalomethanes | 19.169 ug/L | 58.036 ug/L | 80 ug/L | 24% | 15 |
| Haloacetic Acids | 14.325 ug/L | 39.666 ug/L | 60 ug/L | 23.9% | 9 |
| Fluoride | 0.755 mg/L | 1.146 mg/L | 4 mg/L | 18.9% | 14 |
| Copper | 0.238 mg/L | 0.704 mg/L | 1.3 mg/L | 18.3% | 15 |
| Lead | 0.002 mg/L | 0.007 mg/L | 0.015 mg/L | 16.2% | 14 |
| Chromium | 0.013 mg/L | 0.034 mg/L | 0.1 mg/L | 13.3% | 15 |
| Arsenic | 0.001 mg/L | 0.003 mg/L | 0.01 mg/L | 12.5% | 15 |
| Nitrite | 0.124 mg/L | 0.432 mg/L | 1 mg/L | 12.4% | 14 |
Recent violations across county water systems
Showing 10 of 18 recent violations
Water quality in San Bernardino County, California reflects the region's unique combination of water sources, treatment infrastructure, and environmental factors. Our comprehensive analysis examines 15 municipal water systems serving a combined population of over 1,703,202 residents.
The county shows strong water quality performance, with scores ranging from 45/100 in San Bernardino to 93/100 in Rialto. This 48-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 Bernardino County water systems include Total Trihalomethanes, Haloacetic Acids, Fluoride. All monitored contaminants remain within acceptable levels relative to EPA Maximum Contaminant Levels (MCLs).
San Bernardino 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 Bernardino County has an average water quality score of 82/100 (Grade B+) based on analysis of 15 municipal water systems serving 1,703,202 residents.
Rialto has the highest water quality score in San Bernardino County at 93/100. View the detailed report for Rialto.
Most cities in San Bernardino 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.