Tap Water Quality Report
Tap water quality in CORTE MADERA, California
Tap water in CORTE MADERA, California receives a grade of C (78/100) from TapWaterSafety.org. It's served by MARIN MUNICIPAL 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 CORTE MADERA's tap water
Top water quality concerns identified by the EPA and Environmental Working Group across the utility serving CORTE MADERA.
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 21.0 ppb, 350x above the EWG health guideline of 0.06 ppb.
Total trihalomethanes (TTHMs) significantly above health guideline
Moderate concernTotal trihalomethanes (TTHMs) detected at 32.2 ppb, 215x above the EWG health guideline of 0.15 ppb.
EPA compliance record
Official U.S. EPA records for MARIN MUNICIPAL WATER DISTRICT (system ID CA2110002) 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 CORTE MADERA
Filters matched to the specific contaminants in CORTE MADERA'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 CORTE MADERA'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 |
21.0 ppb | 0.06 | — | — | — | — | — | 350× over |
| Total trihalomethanes (TTHMs) Disinfection byproduct |
32.2 ppb | 0.15 | 80.0 | 100 | — | — | — | 215× over |
| Bromodichloromethane Disinfection byproduct |
9.88 ppb | 0.06 | — | — | — | — | — | 165× over |
| Trichloroacetic acid Disinfection byproduct |
6.38 ppb | 0.1 | — | — | — | — | — | 64× over |
| Dibromochloromethane Disinfection byproduct |
4.92 ppb | 0.1 | — | — | — | — | — | 49× over |
| Chloroform Disinfection byproduct |
17.1 ppb | 0.4 | — | — | — | — | — | 43× over |
| Dichloroacetic acid Disinfection byproduct |
7.02 ppb | 0.2 | — | — | — | — | — | 35× over |
| Dibromoacetic acid Disinfection byproduct |
0.784 ppb | 0.03 | — | — | — | — | — | 26× over |
| Chromium (hexavalent) Heavy metal |
0.0542 ppb | 0.02 | — | — | — | — | — | 2.7× over |
| Bromoform Disinfection byproduct |
0.27 ppb | 0.5 | — | — | — | — | — | Below guideline |
| Nitrate and nitrite Inorganic |
0.0524 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | Below guideline |
| Chlorate Disinfection byproduct |
61.6 ppb | 210.0 | — | — | — | — | — | Below guideline |
| Nitrate Inorganic |
0.0148 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | Below guideline |
| Vanadium Other |
0.0834 ppb | 21.0 | — | — | — | — | — | Below guideline |
| Monochloroacetic acid Disinfection byproduct |
0.171 ppb | 53.0 | — | — | — | — | — | Below guideline |
| Strontium Radiological |
0.103 ppb | 1500.0 | — | — | — | — | — | Below guideline |
| Fluoride Inorganic |
0.221 ppm | — | 4.0 | 1.5 | 1.5 | — | — | Below guideline |
| o-toluidine Other |
0.0014 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 MARIN MUNICIPAL WATER DISTRICT.