Tap Water Quality Report
Tap water quality in ANTIOCH, California
Tap water in ANTIOCH, California receives a grade of C (75/100) from TapWaterSafety.org. It's served by CITY OF ANTIOCH. The most significant water quality concerns are: Haloacetic acids (HAA5) significantly above health guideline; Total trihalomethanes (TTHMs) significantly above health guideline; Bromodichloromethane significantly above health guideline. Data sources: EPA SDWIS, EPA ECHO, EWG Tap Water Database.
What's in ANTIOCH's tap water
Top water quality concerns identified by the EPA and Environmental Working Group across the utility serving ANTIOCH.
Haloacetic acids (HAA5) significantly above health guideline
Moderate concernHaloacetic acids (HAA5) detected at 35.3 ppb, 353x above the EWG health guideline of 0.1 ppb.
Total trihalomethanes (TTHMs) significantly above health guideline
Moderate concernTotal trihalomethanes (TTHMs) detected at 48.2 ppb, 322x above the EWG health guideline of 0.15 ppb.
Bromodichloromethane significantly above health guideline
Moderate concernBromodichloromethane detected at 13.9 ppb, 232x above the EWG health guideline of 0.06 ppb.
EPA compliance record
Official U.S. EPA records for CITY OF ANTIOCH (system ID CA0710001) 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 ANTIOCH
Filters matched to the specific contaminants in ANTIOCH'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.
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 ANTIOCH'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 |
35.3 ppb | 0.1 | 60.0 | 60 | — | — | — | 353× over |
| Total trihalomethanes (TTHMs) Disinfection byproduct |
48.2 ppb | 0.15 | 80.0 | 100 | — | — | — | 322× over |
| Bromodichloromethane Disinfection byproduct |
13.9 ppb | 0.06 | — | — | — | — | — | 232× over |
| Haloacetic acids (HAA9) Disinfection byproduct |
9.23 ppb | 0.06 | — | — | — | — | — | 154× over |
| Dibromochloromethane Disinfection byproduct |
13.1 ppb | 0.1 | — | — | — | — | — | 131× over |
| Dibromoacetic acid Disinfection byproduct |
1.28 ppb | 0.03 | — | — | — | — | — | 43× over |
| Chloroform Disinfection byproduct |
16.8 ppb | 0.4 | — | — | — | — | — | 42× over |
| Dichloroacetic acid Disinfection byproduct |
3.11 ppb | 0.2 | — | — | — | — | — | 16× over |
| Trichloroacetic acid Disinfection byproduct |
1.05 ppb | 0.1 | — | — | — | — | — | 11× over |
| Bromoform Disinfection byproduct |
4.23 ppb | 0.5 | — | — | — | — | — | 8.5× over |
| Chromium (hexavalent) Heavy metal |
0.0797 ppb | 0.02 | — | — | — | — | — | 4.0× over |
| Nitrate Inorganic |
0.11 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | Below guideline |
| Bromochloromethane Other |
0.0353 ppb | 0.06 | — | — | — | — | — | Below guideline |
| Nitrate and nitrite Inorganic |
0.03 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | Below guideline |
| Vanadium Other |
2.55 ppb | 21.0 | — | — | — | — | — | Below guideline |
| Chlorate Disinfection byproduct |
13.6 ppb | 210.0 | — | — | — | — | — | Below guideline |
| Molybdenum Other |
0.95 ppb | 40.0 | — | — | — | — | — | Below guideline |
| Manganese Heavy metal |
0.899 ppb | 100.0 | — | 50 | 80 | — | — | Below guideline |
| Monobromoacetic acid Disinfection byproduct |
0.215 ppb | 25.0 | — | — | — | — | — | Below guideline |
| Monochloroacetic acid Disinfection byproduct |
0.0202 ppb | 53.0 | — | — | — | — | — | Below guideline |
| Strontium Radiological |
0.154 ppb | 1500.0 | — | — | — | — | — | Below guideline |
| Bromide Other |
180.0 ppb | — | — | — | — | — | — | Below guideline |
| Fluoride Inorganic |
0.545 ppm | — | 4.0 | 1.5 | 1.5 | — | — | 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 ANTIOCH.