What was found in Simi Valley's water
The level at the city's main supplier, the highest level anywhere in the city, the EPA limit for each, and where every figure comes from.
| Contaminant | Level vs EPA limit | Suppliers | Source |
|---|---|---|---|
| Nitrate-Nitrite | 712500 µg/L 7125% of the EPA limit, at the 95th percentile of samples — 10000 µg/L Main supplier: VENTURA WWD NO. 8 - SIMI VALLEY · 94,738 people · 2019 | 1/2 | SYR4 |
| Nitrate | 2712 µg/L 27% of the EPA limit 10000 µg/L Main supplier: VENTURA WWD NO. 8 - SIMI VALLEY · 94,738 people · 2019 | 1/2 | SYR4 |
| Fluoride | 345 µg/L 8.6% of the EPA limit 4000 µg/L Main supplier: VENTURA WWD NO. 8 - SIMI VALLEY · 94,738 people · 2019 | 1/2 | SYR4 |
| Barium | 120 µg/L 6% of the EPA limit 2000 µg/L Main supplier: VENTURA WWD NO. 8 - SIMI VALLEY · 94,738 people · 2019 | 1/2 | SYR4 |
| Copper | 97.55 µg/L 7.5% of the EPA limit 1300 µg/L Main supplier: VENTURA WWD NO. 8 - SIMI VALLEY · 94,738 people · 2019 | 1/2 | SYR4 |
| Total Haloacetic Acids (HAA5) | 9.775 µg/L 16% of the EPA limit 60 µg/L Main supplier: VENTURA WWD NO. 8 - SIMI VALLEY · 94,738 people · 2019
Highest in the city: 58.2 µg/L — BRANDEIS BARDIN INSTITUTE · 665 people · 2019 | 2/2 | SYR4 |
| TTHM | 41 µg/L 51% of the EPA limit 80 µg/L Main supplier: VENTURA WWD NO. 8 - SIMI VALLEY · 94,738 people · 2019
Highest in the city: 46.8 µg/L — BRANDEIS BARDIN INSTITUTE · 665 people · 2019 | 2/2 | SYR4 |
| Trichloroacetic Acid | 5.935 µg/L No EPA limit set Main supplier: VENTURA WWD NO. 8 - SIMI VALLEY · 94,738 people · 2019
Highest in the city: 33.5 µg/L — BRANDEIS BARDIN INSTITUTE · 665 people · 2019 | 2/2 | SYR4 |
| Selenium | 33.3 µg/L 67% of the EPA limit 50 µg/L Main supplier: VENTURA WWD NO. 8 - SIMI VALLEY · 94,738 people · 2019 | 1/2 | SYR4 |
| Dichloroacetic Acid | 4.5 µg/L No EPA limit set Main supplier: VENTURA WWD NO. 8 - SIMI VALLEY · 94,738 people · 2019
Highest in the city: 25 µg/L — BRANDEIS BARDIN INSTITUTE · 665 people · 2019 | 2/2 | SYR4 |
| Bromoform | 15 µg/L No EPA limit set Main supplier: VENTURA WWD NO. 8 - SIMI VALLEY · 94,738 people · 2019
Highest in the city: 18.62 µg/L — BRANDEIS BARDIN INSTITUTE · 665 people · 2019 | 2/2 | SYR4 |
| Dibromochloromethane | 16.45 µg/L No EPA limit set Main supplier: VENTURA WWD NO. 8 - SIMI VALLEY · 94,738 people · 2019
Highest in the city: 17.94 µg/L — BRANDEIS BARDIN INSTITUTE · 665 people · 2019 | 2/2 | SYR4 |
| Combined Uranium | 16.4719 µg/L 55% of the EPA limit 30 µg/L Main supplier: VENTURA WWD NO. 8 - SIMI VALLEY · 94,738 people · 2019 | 1/2 | SYR4 |
| Monochloroacetic Acid | 8.99 µg/L No EPA limit set Main supplier: VENTURA WWD NO. 8 - SIMI VALLEY · 94,738 people · 2019 | 1/2 | SYR4 |
| Bromodichloromethane | 7.405 µg/L No EPA limit set Main supplier: VENTURA WWD NO. 8 - SIMI VALLEY · 94,738 people · 2019
Highest in the city: 7.84 µg/L — BRANDEIS BARDIN INSTITUTE · 665 people · 2019 | 2/2 | SYR4 |
| Chloroform | 7.74 µg/L No EPA limit set Main supplier: VENTURA WWD NO. 8 - SIMI VALLEY · 94,738 people · 2019 | 2/2 | SYR4 |
| Dibromoacetic Acid | 5.995 µg/L No EPA limit set Main supplier: VENTURA WWD NO. 8 - SIMI VALLEY · 94,738 people · 2019 | 2/2 | SYR4 |
| Arsenic | 3.95 µg/L 40% of the EPA limit 10 µg/L Main supplier: VENTURA WWD NO. 8 - SIMI VALLEY · 94,738 people · 2019 | 1/2 | SYR4 |
| Gross Beta Particle Activity | 3.31 pCi/L No EPA limit set Main supplier: VENTURA WWD NO. 8 - SIMI VALLEY · 94,738 people · 2019 | 1/2 | SYR4 |
| Monobromoacetic Acid | 2.94 µg/L No EPA limit set Main supplier: VENTURA WWD NO. 8 - SIMI VALLEY · 94,738 people · 2019 | 2/2 | SYR4 |
| Lead | 0.0 mg/L 0% of the EPA limit 0.0150 mg/L Main supplier: VENTURA WWD NO. 8 - SIMI VALLEY · 94,738 people · 2025 | 2/2 | LCR |
Each bar shows the measured level as a share of the EPA limit: green is
well under, amber is close to it, red is over. For lead and copper the
limit applies to exactly the 90th-percentile figure shown, so red there
means a real exceedance. For everything else the limit applies to a
running annual average while the figure is the 95th percentile of the
system's samples — over 100% is worth reading, but is not by itself a
violation.
Formal violations are listed separately.
These are the utilities' own EPA-reported results, not a city-wide
average. A detection means the lab measured the
substance — it isn't the same as exceeding a legal limit. Hover a source
tag to see the EPA program and years behind each figure.
Water suppliers serving Simi Valley
| Supplier | Population served |
|---|---|
| VENTURA WWD NO. 8 - SIMI VALLEY | 94,738 |
| BRANDEIS BARDIN INSTITUTE | 665 |
Frequently asked questions about Simi Valley tap water
Is Simi Valley tap water safe to drink?
EPA testing detected 21 contaminants in the water serving Simi Valley. A detection isn't the same as a violation — most detected levels are within federal limits. Check the level and source for each contaminant above, and your utility's annual Consumer Confidence Report for the official compliance status.
How many water suppliers serve Simi Valley?
2 public water suppliers report drinking-water monitoring for Simi Valley, California to the EPA. Each is listed above with its population served.
What contaminants are in Simi Valley's water?
The contaminants EPA monitoring detected in Simi Valley include Nitrate-Nitrite, Nitrate, Fluoride, Barium, Copper. The full list, with the level at the main supplier and the data source, is in the table above.
Where does this data come from?
Every figure is official EPA drinking-water monitoring — the Lead & Copper Rule, the UCMR-5 nationwide testing program, and the EPA Six-Year Review — not our own testing. Each number is labelled with its source and period.