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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 14 cities serving 1,399,075 residents
San Bernardino County in California has an average water quality score of 81/100 (Grade B) based on analysis of 14 municipal water systems. The county's water systems serve approximately 1,399,075 residents.
Overall, San Bernardino County demonstrates good water quality standards. 8 of 14 cities exceed the county average, with Fontana leading with a score of 100/100.
14 cities ranked by water quality score
| Rank | City | Score | Grade | Population |
|---|---|---|---|---|
| 1 | Fontana | 100 | A | 237,700 |
| 2 | Victorville Biggest deduction: Arsenic: 16 of 1400 finished-water samples (2012–2019) above the 10 ug/l MCL (1.1% of samples); max 18 ug/l (−3 pts) | 97 | A | 135,983 |
| 3 | Chino Biggest deduction: Nitrate (as N): 1 of 1971 finished-water samples (2012–2019) above the 10 mg/l MCL (0.1% of samples); max 10.17 mg/l (−3 pts) | 96 | A | 86,435 |
| 4 | San Bernardino Biggest deduction: Other PFAS detected in UCMR5 sampling: PFHxS 4 ppt, PFBS 4.4 ppt, PFPeA 3.4 ppt, PFHxA 4 ppt (−6 pts) | 94 | A | 214,665 |
| 5 | Upland Biggest deduction: Other PFAS detected in UCMR5 sampling: PFBS 3 ppt, PFHxA 5.5 ppt, PFPeA 5.7 ppt (−6 pts) | 94 | A | 78,376 |
| 6 | Chino Hills Biggest deduction: Arsenic: 7 of 179 finished-water samples (2012–2019) above the 10 ug/l MCL (3.9% of samples); max 16 ug/l (−3 pts) | 94 | A | 76,414 |
| 7 | Rialto Biggest deduction: PFOA detected at up to 7.3 ppt in UCMR5 sampling (2024-04-25), at or above EPA's 4 ppt MCL (−10 pts) | 84 | B | 54,453 |
| 8 | Apple Valley Biggest deduction: PFOA detected at up to 5.7 ppt in UCMR5 sampling (2023-09-27), at or above EPA's 4 ppt MCL (−10 pts) | 84 | B | 32,547 |
| 9 | Redlands Biggest deduction: PFOA detected at up to 4.3 ppt in UCMR5 sampling (2024-05-08), at or above EPA's 4 ppt MCL (−10 pts) | 78 | C | 78,025 |
| 10 | Hesperia Biggest deduction: PFOA detected at up to 10.2 ppt in UCMR5 sampling (2025-01-15), at or above EPA's 4 ppt MCL (−10 pts) | 74 | C | 100,744 |
| 11 | Colton Biggest deduction: PFOA detected at up to 5.9 ppt in UCMR5 sampling (2025-02-27), at or above EPA's 4 ppt MCL (−10 pts) | 73 | C | 46,525 |
| 12 | Highland Biggest deduction: PFOA detected at up to 18 ppt in UCMR5 sampling (2025-01-09), at or above EPA's 4 ppt MCL (−10 pts) | 73 | C | 20,188 |
| 13 | Ontario Biggest deduction: PFOA detected at up to 30 ppt in UCMR5 sampling (2024-02-28), at or above EPA's 4 ppt MCL (−10 pts) | 64 | D | 185,010 |
| 14 | Yucaipa Biggest deduction: 3 health-based violations (MCL/treatment-technique) in the last 5 years (−30 pts) | 34 | F | 52,010 |
Real EPA readings across county water systems (lead: latest 90th percentile; PFAS: UCMR5 2023–2026; others: 2012–2019 averages)
| Contaminant | Avg Level | Max Level | EPA Limit | % of Limit | Cities |
|---|---|---|---|---|---|
| PFAS (PFOA/PFOS max, UCMR5) | 7.507 ppt | 30 ppt | 4 ppt | 187.7% | 14 |
| Nitrate (2012–2019 avg) | 3.919 mg/L | 6.075 mg/L | 10 mg/L | 39.2% | 12 |
| TTHM (2012–2019 avg) | 17.18 ug/L | 44.421 ug/L | 80 ug/L | 21.5% | 14 |
| Arsenic (2012–2019 avg) | 1.58 ug/L | 4.928 ug/L | 10 ug/L | 15.8% | 6 |
| Fluoride (2012–2019 avg) | 0.387 mg/L | 0.66 mg/L | 4 mg/L | 9.7% | 6 |
| HAA5 (2012–2019 avg) | 4.096 ug/L | 15.459 ug/L | 60 ug/L | 6.8% | 14 |
| Lead (90th percentile) | 0.543 ppb | 2.9 ppb | 15 ppb | 3.6% | 14 |
| Uranium (2012–2019 avg) | 1.046 ug/L | 1.495 ug/L | 30 ug/L | 3.5% | 2 |
Recent violations across county water systems
Health-based: Treatment technique — Failure to Filter (SWTR) - Long Term 2 Enhanced Surface Water Treatment Rule
3/16/2026
Health-based: MCL exceeded — Maximum Contaminant Level Violation, Single Sample - Nitrate
3/31/2023
Health-based: MCL exceeded — Maximum Contaminant Level Violation, Single Sample - Nitrate
6/30/2019
Showing 10 of 13 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 14 municipal water systems serving a combined population of over 1,399,075 residents.
The county shows strong water quality performance, with scores ranging from 34/100 in Yucaipa to 100/100 in Fontana. This 66-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 PFAS (PFOA/PFOS max, UCMR5), Nitrate (2012–2019 avg), TTHM (2012–2019 avg). At least one reading averages above 50% of its EPA limit across the county's systems, worth attention from residents and utilities.
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 81/100 (Grade B) based on analysis of 14 municipal water systems serving 1,399,075 residents.
Fontana has the highest water quality score in San Bernardino County at 100/100. View the detailed report for Fontana.
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.