Tap Water Quality Report
Tap water quality in MOUNTAIN VIEW, California
Tap water in MOUNTAIN VIEW, California receives a grade of C (70/100) from TapWaterSafety.org. It's served by CITY OF MOUNTAIN VIEW. The most significant water quality concerns are: Haloacetic acids (HAA9) significantly above health guideline; Haloacetic acids (HAA5) significantly above health guideline; Total trihalomethanes (TTHMs) significantly above health guideline. Data sources: EPA SDWIS, EPA ECHO, EWG Tap Water Database.
What's in MOUNTAIN VIEW's tap water
Top water quality concerns identified by the EPA and Environmental Working Group across the utility serving MOUNTAIN VIEW.
Haloacetic acids (HAA9) significantly above health guideline
Moderate concernHaloacetic acids (HAA9) detected at 29.9 ppb, 499x above the EWG health guideline of 0.06 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.
Total trihalomethanes (TTHMs) significantly above health guideline
Moderate concernTotal trihalomethanes (TTHMs) detected at 49.1 ppb, 328x above the EWG health guideline of 0.15 ppb.
EPA compliance record
Official U.S. EPA records for CITY OF MOUNTAIN VIEW (system ID CA4310007) 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 MOUNTAIN VIEW
Filters matched to the specific contaminants in MOUNTAIN VIEW'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 MOUNTAIN VIEW'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 (HAA9) Disinfection byproduct |
29.9 ppb | 0.06 | — | — | — | — | — | 499× over |
| Haloacetic acids (HAA5) Disinfection byproduct |
36.2 ppb | 0.1 | 60.0 | 60 | — | — | — | 362× over |
| Total trihalomethanes (TTHMs) Disinfection byproduct |
49.1 ppb | 0.15 | 80.0 | 100 | — | — | — | 328× over |
| Trichloroacetic acid Disinfection byproduct |
13.6 ppb | 0.1 | — | — | — | — | — | 136× over |
| Bromodichloromethane Disinfection byproduct |
6.95 ppb | 0.06 | — | — | — | — | — | 116× over |
| Dibromoacetic acid Disinfection byproduct |
3.19 ppb | 0.03 | — | — | — | — | — | 106× over |
| Dichloroacetic acid Disinfection byproduct |
17.2 ppb | 0.2 | — | — | — | — | — | 86× over |
| Dibromochloromethane Disinfection byproduct |
8.31 ppb | 0.1 | — | — | — | — | — | 83× over |
| Chloroform Disinfection byproduct |
29.6 ppb | 0.4 | — | — | — | — | — | 74× over |
| Nitrate Inorganic |
4.88 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 35× over |
| Chromium (hexavalent) Heavy metal |
0.312 ppb | 0.02 | — | — | — | — | — | 16× over |
| Bromoform Disinfection byproduct |
4.24 ppb | 0.5 | — | — | — | — | — | 8.5× over |
| Chlorate Disinfection byproduct |
122.5 ppb | 210.0 | — | — | — | — | — | Below guideline |
| Barium Heavy metal |
140.0 ppb | 700.0 | 2000.0 | — | 1300 | 2000 | — | Below guideline |
| Vanadium Other |
2.68 ppb | 21.0 | — | — | — | — | — | Below guideline |
| Molybdenum Other |
0.815 ppb | 40.0 | — | — | — | — | — | Below guideline |
| Manganese Heavy metal |
0.838 ppb | 100.0 | — | 50 | 80 | — | — | Below guideline |
| Monochloroacetic acid Disinfection byproduct |
0.245 ppb | 53.0 | — | — | — | — | — | Below guideline |
| Monobromoacetic acid Disinfection byproduct |
0.076 ppb | 25.0 | — | — | — | — | — | Below guideline |
| Strontium Radiological |
0.188 ppb | 1500.0 | — | — | — | — | — | Below guideline |
| Chlorodifluoromethane Other |
0.0669 ppb | — | — | — | — | — | — | Below guideline |
| Fluoride Inorganic |
0.0781 ppm | — | 4.0 | 1.5 | 1.5 | — | — | Below guideline |
| Lithium Other |
0.581 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 MOUNTAIN VIEW.