Tap Water Quality Report
Tap water quality in WALNUT, California
Tap water in WALNUT, California receives a grade of D (67/100) from TapWaterSafety.org. It's served by WALNUT VALLEY 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 WALNUT's tap water
Top water quality concerns identified by the EPA and Environmental Working Group across the utility serving WALNUT.
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.
Haloacetic acids (HAA9) significantly above health guideline
Moderate concernHaloacetic acids (HAA9) detected at 20.8 ppb, 346x above the EWG health guideline of 0.06 ppb.
Total trihalomethanes (TTHMs) significantly above health guideline
Moderate concernTotal trihalomethanes (TTHMs) detected at 25.0 ppb, 167x above the EWG health guideline of 0.15 ppb.
Recommended filters for WALNUT
Filters matched to the specific contaminants in WALNUT's water supply.
Carbon block (NSF/ANSI 42 + 53)
$40-$750Activated carbon is highly effective for disinfection byproducts like TTHM and HAA5.
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 WALNUT'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 |
| Haloacetic acids (HAA9) Disinfection byproduct |
20.8 ppb | 0.06 | — | — | — | — | — | 346× over |
| Total trihalomethanes (TTHMs) Disinfection byproduct |
25.0 ppb | 0.15 | 80.0 | 100 | — | — | — | 167× over |
| Bromodichloromethane Disinfection byproduct |
7.79 ppb | 0.06 | — | — | — | — | — | 130× over |
| Dibromochloromethane Disinfection byproduct |
8.24 ppb | 0.1 | — | — | — | — | — | 82× over |
| Dibromoacetic acid Disinfection byproduct |
1.64 ppb | 0.03 | — | — | — | — | — | 55× over |
| Dichloroacetic acid Disinfection byproduct |
4.59 ppb | 0.2 | — | — | — | — | — | 23× over |
| Chloroform Disinfection byproduct |
7.18 ppb | 0.4 | — | — | — | — | — | 18× over |
| Trichloroacetic acid Disinfection byproduct |
1.66 ppb | 0.1 | — | — | — | — | — | 17× over |
| Chromium (hexavalent) Heavy metal |
0.221 ppb | 0.02 | — | — | — | — | — | 11× over |
| Bromoform Disinfection byproduct |
3.38 ppb | 0.5 | — | — | — | — | — | 6.8× over |
| Chlorate Disinfection byproduct |
36.5 ppb | 210.0 | — | — | — | — | — | Below guideline |
| Vanadium Other |
2.96 ppb | 21.0 | — | — | — | — | — | Below guideline |
| Molybdenum Other |
4.2 ppb | 40.0 | — | — | — | — | — | Below guideline |
| Manganese Heavy metal |
1.9 ppb | 100.0 | — | 50 | 80 | — | — | Below guideline |
| Monochloroacetic acid Disinfection byproduct |
0.139 ppb | 53.0 | — | — | — | — | — | Below guideline |
| Monobromoacetic acid Disinfection byproduct |
0.0268 ppb | 25.0 | — | — | — | — | — | Below guideline |
| Strontium Radiological |
0.712 ppb | 1500.0 | — | — | — | — | — | Below guideline |
| 1-Butanol Other |
0.288 ppb | — | — | — | — | — | — | Below guideline |
| 4-Androstene-3,17-dione Other |
0.051 ppt | — | — | — | — | — | — | Below guideline |
| Lithium Other |
21.7 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 WALNUT VALLEY WATER DISTRICT.