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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 394,951 residents
Ventura County in California has an average water quality score of 100/100 (Grade A) based on analysis of 4 municipal water systems. The county's water systems serve approximately 394,951 residents.
Overall, Ventura County demonstrates good water quality standards. 3 of 4 cities exceed the county average, with Camarillo leading with a score of 100/100.
4 cities ranked by water quality score
| Rank | City | Score | Grade | Population |
|---|---|---|---|---|
| 1 | Oxnard | 100 | A | 200,232 |
| 2 | Thousand Oaks | 100 | A | 53,157 |
| 3 | Camarillo | 100 | A | 46,824 |
| 4 | Simi Valley Biggest deduction: 1 monitoring/reporting violation in the last 5 years (−1 pts) | 99 | A | 94,738 |
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 |
|---|---|---|---|---|---|
| TTHM (2012–2019 avg) | 21.955 ug/L | 24.298 ug/L | 80 ug/L | 27.4% | 4 |
| Uranium (2012–2019 avg) | 6.342 ug/L | 8.314 ug/L | 30 ug/L | 21.1% | 2 |
| Nitrate (2012–2019 avg) | 1.815 mg/L | 2.852 mg/L | 10 mg/L | 18.2% | 2 |
| HAA5 (2012–2019 avg) | 5.685 ug/L | 6.212 ug/L | 60 ug/L | 9.5% | 4 |
| Fluoride (2012–2019 avg) | 0.276 mg/L | 0.503 mg/L | 4 mg/L | 6.9% | 2 |
| Arsenic (2012–2019 avg) | 0.338 ug/L | 0.4 ug/L | 10 ug/L | 3.4% | 2 |
| Lead (90th percentile) | 0 ppb | 0 ppb | 15 ppb | 0% | 4 |
| PFAS (PFOA/PFOS max, UCMR5) | 0 ppt | 0 ppt | 4 ppt | 0% | 4 |
Recent violations across county water systems
Water quality in Ventura 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 394,951 residents.
The county shows strong water quality performance, with scores ranging from 99/100 in Simi Valley to 100/100 in Camarillo. This 1-point spread indicates relatively consistent water quality standards across municipal systems.
The most prevalent contaminants detected across Ventura County water systems include TTHM (2012–2019 avg), Uranium (2012–2019 avg), Nitrate (2012–2019 avg). Every county-wide average sits below 50% of its EPA Maximum Contaminant Level (MCL).
Ventura 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.
Ventura County has an average water quality score of 100/100 (Grade A) based on analysis of 4 municipal water systems serving 394,951 residents.
Camarillo has the highest water quality score in Ventura County at 100/100. View the detailed report for Camarillo.
Most cities in Ventura 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.