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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 5 cities serving 629,241 residents
Ventura County in California has an average water quality score of 79/100 (Grade B) based on analysis of 5 municipal water systems. The county's water systems serve approximately 629,241 residents.
Water quality in Ventura County is fair, with some cities showing room for improvement. 1 cities have scores below 70, indicating elevated contaminant levels that residents should be aware of. Simi Valley has the best water quality at 96/100.
5 cities ranked by water quality score
| Rank | City | Score | Grade | Population |
|---|---|---|---|---|
| 1 | Simi Valley Top concern: Total Trihalomethanes (21.3% of limit) | 96 | A+ | 130,228 |
| 2 | Oxnard Top concern: Total Trihalomethanes (21.7% of limit) | 87 | A- | 201,528 |
| 3 | Camarillo Top concern: Haloacetic Acids (36.1% of limit) | 83 | B+ | 65,406 |
| 4 | Thousand Oaks Top concern: Arsenic (14.6% of limit) | 81 | B+ | 122,083 |
| 5 | San Buenaventura Top concern: Haloacetic Acids (74.3% of limit) | 49 | F | 109,996 |
Top detected contaminants across county water systems
| Contaminant | Avg Level | Max Level | EPA Limit | % of Limit | Cities |
|---|---|---|---|---|---|
| Haloacetic Acids | 21.419 ug/L | 44.6 ug/L | 60 ug/L | 35.7% | 4 |
| Lead | 0.003 mg/L | 0.008 mg/L | 0.015 mg/L | 22.8% | 5 |
| Mercury | 0 mg/L | 0.001 mg/L | 0.002 mg/L | 21.3% | 4 |
| Total Trihalomethanes | 15.907 ug/L | 29.422 ug/L | 80 ug/L | 19.9% | 5 |
| Fluoride | 0.697 mg/L | 0.986 mg/L | 4 mg/L | 17.4% | 5 |
| Arsenic | 0.002 mg/L | 0.004 mg/L | 0.01 mg/L | 17% | 4 |
| Chromium | 0.017 mg/L | 0.044 mg/L | 0.1 mg/L | 16.5% | 5 |
| Copper | 0.19 mg/L | 0.304 mg/L | 1.3 mg/L | 14.6% | 5 |
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 5 municipal water systems serving a combined population of over 629,241 residents.
The county shows moderate water quality performance, with scores ranging from 49/100 in San Buenaventura to 96/100 in Simi Valley. This 47-point spread indicates significant variation in water quality across the county, suggesting different water sources or treatment approaches.
The most prevalent contaminants detected across Ventura County water systems include Haloacetic Acids, Lead, Mercury. All monitored contaminants remain within acceptable levels relative to EPA Maximum Contaminant Levels (MCLs).
Water quality in Ventura County is fair but shows room for improvement. Residents in cities scoring below 70 should consider water filtration, particularly for drinking and cooking. Check your specific city's report above for personalized recommendations.
Ventura County has an average water quality score of 79/100 (Grade B) based on analysis of 5 municipal water systems serving 629,241 residents.
Simi Valley has the highest water quality score in Ventura County at 96/100. View the detailed report for Simi Valley.
Given the water quality variation across Ventura County, we recommend reviewing your specific city's water quality report. 1 cities have scores below 70, where filtration is particularly recommended.
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.