Tap Water Quality Report
Tap water quality in CONCORD, California
Tap water in CONCORD, California receives a grade of C (76/100) from TapWaterSafety.org. It's served by CONTRA COSTA WATER DISTRICT. The most significant water quality concerns are: Haloacetic acids (HAA5) significantly above health guideline; Haloacetic acids (HAA9) significantly above health guideline; Total trihalomethanes (TTHMs) significantly above health guideline. Data sources: EPA SDWIS, EPA ECHO, EWG Tap Water Database.
What's in CONCORD's tap water
Top water quality concerns identified by the EPA and Environmental Working Group across the utility serving CONCORD.
Haloacetic acids (HAA5) significantly above health guideline
Moderate concernHaloacetic acids (HAA5) detected at 35.6 ppb, 356x above the EWG health guideline of 0.1 ppb.
Haloacetic acids (HAA9) significantly above health guideline
Moderate concernHaloacetic acids (HAA9) detected at 11.2 ppb, 186x above the EWG health guideline of 0.06 ppb.
Total trihalomethanes (TTHMs) significantly above health guideline
Moderate concernTotal trihalomethanes (TTHMs) detected at 17.9 ppb, 119x above the EWG health guideline of 0.15 ppb.
EPA compliance record
Official U.S. EPA records for CONTRA COSTA WATER DISTRICT (system ID CA0710003) 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 CONCORD
Filters matched to the specific contaminants in CONCORD'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 CONCORD'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 |
35.6 ppb | 0.1 | 60.0 | 60 | — | — | — | 356× over |
| Haloacetic acids (HAA9) Disinfection byproduct |
11.2 ppb | 0.06 | — | — | — | — | — | 186× over |
| Total trihalomethanes (TTHMs) Disinfection byproduct |
17.9 ppb | 0.15 | 80.0 | 100 | — | — | — | 119× over |
| Dibromoacetic acid Disinfection byproduct |
3.43 ppb | 0.03 | — | — | — | — | — | 114× over |
| Bromodichloromethane Disinfection byproduct |
4.95 ppb | 0.06 | — | — | — | — | — | 83× over |
| Dibromochloromethane Disinfection byproduct |
5.2 ppb | 0.1 | — | — | — | — | — | 52× over |
| Dichloroacetic acid Disinfection byproduct |
5.08 ppb | 0.2 | — | — | — | — | — | 25× over |
| Bromate Disinfection byproduct |
2.31 ppb | 0.1 | 10.0 | 10 | 10 | 0.1 | — | 23× over |
| Chloroform Disinfection byproduct |
3.73 ppb | 0.4 | — | — | — | — | — | 9.3× over |
| Trichloroacetic acid Disinfection byproduct |
0.925 ppb | 0.1 | — | — | — | — | — | 9.3× over |
| Bromoform Disinfection byproduct |
3.29 ppb | 0.5 | — | — | — | — | — | 6.6× over |
| Chromium (hexavalent) Heavy metal |
0.0568 ppb | 0.02 | — | — | — | — | — | 2.8× over |
| Nitrate Inorganic |
0.39 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 2.8× over |
| Nitrate and nitrite Inorganic |
0.272 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 1.9× over |
| Bromochloromethane Other |
0.0184 ppb | 0.06 | — | — | — | — | — | Below guideline |
| Manganese Heavy metal |
16.7 ppb | 100.0 | — | 50 | 80 | — | — | Below guideline |
| Chlorate Disinfection byproduct |
34.4 ppb | 210.0 | — | — | — | — | — | Below guideline |
| Vanadium Other |
2.44 ppb | 21.0 | — | — | — | — | — | Below guideline |
| Molybdenum Other |
1.13 ppb | 40.0 | — | — | — | — | — | Below guideline |
| Monobromoacetic acid Disinfection byproduct |
0.418 ppb | 25.0 | — | — | — | — | — | Below guideline |
| Monochloroacetic acid Disinfection byproduct |
0.679 ppb | 53.0 | — | — | — | — | — | Below guideline |
| Strontium Radiological |
0.154 ppb | 1500.0 | — | — | — | — | — | Below guideline |
| Bromide Other |
64.0 ppb | — | — | — | — | — | — | Below guideline |
| Fluoride Inorganic |
0.28 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 CONTRA COSTA WATER DISTRICT.