Tap Water Quality Report
Tap water quality in WESTMINSTER, California
Tap water in WESTMINSTER, California receives a grade of F (55/100) from TapWaterSafety.org. It's served by CITY OF WESTMINSTER. The most significant water quality concerns are: PFAS contamination; Perfluorohexane sulfonate (PFHXS) significantly above health guideline; Arsenic significantly above health guideline; Haloacetic acids (HAA5) significantly above health guideline. Data sources: EPA SDWIS, EPA ECHO, EWG Tap Water Database.
What's in WESTMINSTER's tap water
Top water quality concerns identified by the EPA and Environmental Working Group across the utility serving WESTMINSTER.
PFAS contamination
Severe concernPerfluorooctane sulfonate (PFOS), Perfluorooctanoic acid (PFOA) detected. PFAS are persistent chemicals linked to cancer and immune effects with no known safe exposure threshold.
Perfluorohexane sulfonate (PFHXS) significantly above health guideline
Moderate concernPerfluorohexane sulfonate (PFHXS) detected at 1.12 ppt, 1118x above the EWG health guideline of 0.001 ppt.
Arsenic significantly above health guideline
Moderate concernArsenic detected at 1.91 ppb, 478x above the EWG health guideline of 0.004 ppb.
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.
EPA compliance record
Official U.S. EPA records for CITY OF WESTMINSTER (system ID CA3010064) 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 WESTMINSTER
Filters matched to the specific contaminants in WESTMINSTER's water supply.
Filter certified for PFOA/PFOS (NSF/ANSI 53 or 58)
$180-$750Reverse osmosis and some carbon block filters reduce PFAS. Look for certification to NSF/ANSI 53 or 58 for PFOA/PFOS.
Reverse osmosis certified for arsenic (NSF/ANSI 58)
$429-$599Reverse osmosis certified under NSF/ANSI 58 for arsenic is the most reliable home option.
Carbon filter certified for VOCs (NSF/ANSI 53)
$180-$599Activated carbon is effective for disinfection byproducts. Look for NSF/ANSI 53 VOC reduction.
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 WESTMINSTER'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 |
|---|---|---|---|---|---|---|---|---|
| Perfluorohexane sulfonate (PFHXS) PFAS |
1.12 ppt | 0.001 | 10.0 | — | — | — | — | 1118× over |
| Arsenic Heavy metal |
1.91 ppb | 0.004 | 10.0 | 10 | 10 | 0.004 | — | 478× over |
| Haloacetic acids (HAA5) Disinfection byproduct |
36.2 ppb | 0.1 | 60.0 | 60 | — | — | — | 362× over |
| Chromium (hexavalent) Heavy metal |
0.846 ppb | 0.02 | — | — | — | — | — | 42× over |
| Haloacetic acids (HAA9) Disinfection byproduct |
2.23 ppb | 0.06 | — | — | — | — | — | 37× over |
| Nitrate and nitrite Inorganic |
2.35 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 17× over |
| Nitrate Inorganic |
2.2 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 16× over |
| Uranium Radiological |
5.76 pCi/L | 0.43 | 20.0 | 30 | 30 | 0.43 | — | 13× over |
| Total trihalomethanes (TTHMs) Disinfection byproduct |
1.03 ppb | 0.15 | 80.0 | 100 | — | — | — | 6.8× over |
| Perfluorooctanoic acid (PFOA) PFAS |
0.442 ppt | 0.09 | 4.0 | 100 | 100 | 0.007 | — | 4.9× over |
| Dibromochloromethane Disinfection byproduct |
0.449 ppb | 0.1 | — | — | — | — | — | 4.5× over |
| Dibromoacetic acid Disinfection byproduct |
0.109 ppb | 0.03 | — | — | — | — | — | 3.6× over |
| Perfluorooctane sulfonate (PFOS) PFAS |
0.947 ppt | 0.3 | 4.0 | 100 | 100 | 1 | — | 3.2× over |
| Trichloroacetic acid Disinfection byproduct |
0.222 ppb | 0.1 | — | — | — | — | — | 2.2× over |
| Bromodichloromethane Disinfection byproduct |
0.0997 ppb | 0.06 | — | — | — | — | — | 1.7× over |
| Perchlorate Disinfection byproduct |
1.35 ppb | 1.0 | — | — | — | — | — | 1.4× over |
| Dichloroacetic acid Disinfection byproduct |
0.259 ppb | 0.2 | — | — | — | — | — | 1.3× over |
| Radium, combined (-226 and -228) Radiological |
0.06 pCi/L | 0.05 | 5.0 | — | — | — | — | 1.2× over |
| Bromoform Disinfection byproduct |
0.341 ppb | 0.5 | — | — | — | — | — | Below guideline |
| Chlorate Disinfection byproduct |
53.1 ppb | 210.0 | — | — | — | — | — | Below guideline |
| Vanadium Other |
2.82 ppb | 21.0 | — | — | — | — | — | Below guideline |
| Molybdenum Other |
5.35 ppb | 40.0 | — | — | — | — | — | Below guideline |
| Chloroform Disinfection byproduct |
0.0382 ppb | 0.4 | — | — | — | — | — | Below guideline |
| Barium Heavy metal |
54.4 ppb | 700.0 | 2000.0 | — | 1300 | 2000 | — | Below guideline |
| 1,4-Dioxane Semi-volatile organic compound |
0.0126 ppb | 0.35 | — | — | 50 | 1 | — | Below guideline |
| Manganese Heavy metal |
1.66 ppb | 100.0 | — | 50 | 80 | — | — | Below guideline |
| Strontium Radiological |
0.676 ppb | 1500.0 | — | — | — | — | — | Below guideline |
| Aluminum Heavy metal |
0.11 ppb | 600.0 | — | 200 | — | 600 | — | Below guideline |
| Bromide Other |
96.5 ppb | — | — | — | — | — | — | Below guideline |
| Fluoride Inorganic |
0.472 ppm | — | 4.0 | 1.5 | 1.5 | — | — | Below guideline |
| Germanium Other |
0.015 ppb | — | — | — | — | — | — | Below guideline |
| Lithium Other |
7.64 ppb | — | — | — | — | — | — | 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 CITY OF WESTMINSTER.