Tap Water Quality Report
Tap water quality in SIMI VALLEY, California
Tap water in SIMI VALLEY, California receives a grade of D (65/100) from TapWaterSafety.org. It's served by VENTURA WWD NO. 8 - SIMI VALLEY. The most significant water quality concerns are: Haloacetic acids (HAA5) significantly above health guideline; Radon* significantly above health guideline; Haloacetic acids (HAA9) significantly above health guideline; Arsenic detected. Data sources: EPA SDWIS, EPA ECHO, EWG Tap Water Database.
What's in SIMI VALLEY's tap water
Top water quality concerns identified by the EPA and Environmental Working Group across the utility serving SIMI VALLEY.
Haloacetic acids (HAA5) significantly above health guideline
Moderate concernHaloacetic acids (HAA5) detected at 36.2 ppb, 362x above the EWG health guideline of 0.1 ppb.
Radon* significantly above health guideline
Moderate concernRadon* detected at 258.72 pCi/L, 172x above the EWG health guideline of 1.5 pCi/L.
Haloacetic acids (HAA9) significantly above health guideline
Moderate concernHaloacetic acids (HAA9) detected at 10.2 ppb, 171x above the EWG health guideline of 0.06 ppb.
Arsenic detected
Moderate concernArsenic detected at 0.494 ppb.
EPA compliance record
Official U.S. EPA records for VENTURA WWD NO. 8 - SIMI VALLEY (system ID CA5610023) for the last 3 years. Checked 2026-10-07.
Source: U.S. EPA Enforcement and Compliance History Online (ECHO), from the Safe Drinking Water Information System. See EPA's full report.
Recommended filters for SIMI VALLEY
Filters matched to the specific contaminants in SIMI VALLEY's water supply.
Carbon filter certified for VOCs (NSF/ANSI 53)
$180-$599Activated carbon is effective for disinfection byproducts. Look for NSF/ANSI 53 VOC reduction.
Reverse osmosis certified for arsenic (NSF/ANSI 58)
$429-$599Reverse osmosis certified under NSF/ANSI 58 for arsenic is the most reliable home option.
Disclosure: TapWaterSafety earns a commission from purchases made through these links. This does not influence our scoring methodology or filter selection.
All contaminants detected in SIMI VALLEY's tap water
Every contaminant identified, compared side-by-side against US EPA legal limits, the EU Drinking Water Directive (2020/2184), WHO Guidelines, and California's Public Health Goal. Why we show multiple standards →
| Contaminant | Detected | EWG US health-based |
EPA US legal |
EU DWD Europe |
WHO global |
CA PHG strictest US |
Tested sample year |
Status |
|---|---|---|---|---|---|---|---|---|
| Haloacetic acids (HAA5) Disinfection byproduct |
36.2 ppb | 0.1 | 60.0 | 60 | — | — | — | 362× over |
| Radon* Radiological |
258.72 pCi/L | 1.5 | — | — | — | — | — | 172× over |
| Haloacetic acids (HAA9) Disinfection byproduct |
10.2 ppb | 0.06 | — | — | — | — | — | 171× over |
| Total trihalomethanes (TTHMs) Disinfection byproduct |
22.3 ppb | 0.15 | 80.0 | 100 | — | — | — | 149× over |
| Arsenic Heavy metal |
0.494 ppb | 0.004 | 10.0 | 10 | 10 | 0.004 | — | 124× over |
| Dibromoacetic acid Disinfection byproduct |
3.31 ppb | 0.03 | — | — | — | — | — | 110× over |
| Dibromochloromethane Disinfection byproduct |
8.24 ppb | 0.1 | — | — | — | — | — | 82× over |
| Bromodichloromethane Disinfection byproduct |
4.06 ppb | 0.06 | — | — | — | — | — | 68× over |
| Bromoform Disinfection byproduct |
8.06 ppb | 0.5 | — | — | — | — | — | 16× over |
| Uranium Radiological |
5.95 pCi/L | 0.43 | 20.0 | 30 | 30 | 0.43 | — | 14× over |
| Bromochloromethane* Other |
0.698 ppb | 0.06 | — | — | — | — | — | 12× over |
| Dichloroacetic acid Disinfection byproduct |
1.56 ppb | 0.2 | — | — | — | — | — | 7.8× over |
| Chromium (hexavalent) Heavy metal |
0.117 ppb | 0.02 | — | — | — | — | — | 5.9× over |
| Chloroform Disinfection byproduct |
1.91 ppb | 0.4 | — | — | — | — | — | 4.8× over |
| Nitrate and nitrite Inorganic |
0.663 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 4.7× over |
| Radium, combined (-226 and -228) Radiological |
0.22 pCi/L | 0.05 | 5.0 | — | — | — | — | 4.3× over |
| Nitrate Inorganic |
0.442 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 3.2× over |
| Trichloroacetic acid Disinfection byproduct |
0.324 ppb | 0.1 | — | — | — | — | — | 3.2× over |
| Chlorate Disinfection byproduct |
99.1 ppb | 210.0 | — | — | — | — | — | Below guideline |
| Selenium Heavy metal |
8.39 ppb | 30.0 | 50.0 | 20 | 40 | 30 | — | Below guideline |
| Vanadium Other |
3.73 ppb | 21.0 | — | — | — | — | — | Below guideline |
| Molybdenum Other |
6.88 ppb | 40.0 | — | — | — | — | — | Below guideline |
| Dichloromethane (methylene chloride)* Volatile organic compound |
0.323 ppb | 4.0 | 5.0 | — | — | — | — | Below guideline |
| Aluminum Heavy metal |
16.8 ppb | 600.0 | — | 200 | — | 600 | — | Below guideline |
| Barium Heavy metal |
16.4 ppb | 700.0 | 2000.0 | — | 1300 | 2000 | — | Below guideline |
| Monochloroacetic acid* Disinfection byproduct |
1.07 ppb | 53.0 | — | — | — | — | — | Below guideline |
| Monobromoacetic acid Disinfection byproduct |
0.235 ppb | 25.0 | — | — | — | — | — | Below guideline |
| Manganese Heavy metal |
0.387 ppb | 100.0 | — | 50 | 80 | — | — | Below guideline |
| Strontium Radiological |
0.268 ppb | 1500.0 | — | — | — | — | — | Below guideline |
| Xylenes (total)* Volatile organic compound |
0.0318 ppb | 1800.0 | 10000.0 | — | — | — | — | Below guideline |
| Dibromomethane* Other |
1.33 ppb | — | — | — | — | — | — | Below guideline |
| Fluoride Inorganic |
0.324 ppm | — | 4.0 | 1.5 | 1.5 | — | — | Below guideline |
| Nitrite* Inorganic |
0.0128 ppm | — | 1.0 | — | — | — | — | Below guideline |
All values in the unit of the detected level. Red cells indicate the detected level exceeds that standard. Some contaminants have limits in some jurisdictions but not others (shown as —). The "Tested" column shows the year each contaminant sample was collected.
Sources: US EPA, EU Drinking Water Directive 2020/2184, WHO Guidelines, California OEHHA PHGs, EWG Tap Water Database.
Treatment plant contact info
For service issues, water quality concerns, or to request a Consumer Confidence Report from VENTURA WWD NO. 8 - SIMI VALLEY.