Water Quality Report · Updated October 07, 2026
WESTCHESTER JOINT WATER WORKS
WESTCHESTER JOINT WATER WORKS delivers tap water graded F (48/100) by TapWaterSafety.org. The utility serves approximately 59,629 residents in MAMARONECK, New York using surface water. The most significant water quality concerns are: PFAS contamination; Haloacetic acids (HAA9) significantly above health guideline; Haloacetic acids (HAA5) significantly above health guideline; Trichloroacetic acid significantly above health guideline. For questions, the utility can be reached at 914-777-7722.
Is MAMARONECK tap water safe to drink?
WESTCHESTER JOINT WATER WORKS delivers tap water that earns a grade of F (48/100) from TapWaterSafety.org — a poor rating, with significant contamination concerns and/or recent violations.
The utility serves 59,629 residents in MAMARONECK, drawing from surface water.
Public testing data identifies 10 contaminants in this water above EWG's health-based guidelines, including: Haloacetic acids (HAA9), Haloacetic acids (HAA5), Trichloroacetic acid, Total trihalomethanes (TTHMs), Dichloroacetic acid, Chloroform, Bromochloroacetic acid, Bromodichloromethane, Chromium (hexavalent), Nitrate and nitrite. For most residents, a properly certified home filter at the kitchen tap is the most cost-effective way to reduce exposure to whatever's in your water. See our filter recommendations below, matched specifically to this utility's contaminant profile.
EPA compliance record
Official U.S. EPA records for WESTCHESTER JOINT WATER WORKS (system ID NY5903435) for the last 3 years. Checked 2026-10-07.
| Rule | Type | Since | Status |
|---|---|---|---|
| Surface Water Treatment Rule | Required treatment not met | 06/30/1993 | Open |
Source: U.S. EPA Enforcement and Compliance History Online (ECHO), from the Safe Drinking Water Information System. See EPA's full report.
Quick actions for MAMARONECK residents
Top concerns in this water
Based on the most recent EPA and EWG data, these are the most significant water quality issues for WESTCHESTER JOINT WATER WORKS.
PFAS contamination
Severe concernPerfluorooctane sulfonate (PFOS) detected. PFAS are persistent chemicals linked to cancer and immune effects with no known safe exposure threshold.
Haloacetic acids (HAA9) significantly above health guideline
Moderate concernHaloacetic acids (HAA9) detected at 55.8 ppb, 929x above the EWG health guideline of 0.06 ppb.
Haloacetic acids (HAA5) significantly above health guideline
Moderate concernHaloacetic acids (HAA5) detected at 41.0 ppb, 410x above the EWG health guideline of 0.1 ppb.
Trichloroacetic acid significantly above health guideline
Moderate concernTrichloroacetic acid detected at 26.7 ppb, 267x above the EWG health guideline of 0.1 ppb.
Contact WESTCHESTER JOINT WATER WORKS
Reach the utility directly for service issues, water quality concerns, or to request your Consumer Confidence Report.
General Contact
Treatment Plant
Recommended water filters for MAMARONECK
Filters matched to the specific contaminants in this water supply.
Filter certified for PFOA/PFOS (NSF/ANSI 53 or 58)
$180-$750Reverse osmosis and some carbon block filters reduce PFAS. Look for certification to NSF/ANSI 53 or 58 for PFOA/PFOS.
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.
Score breakdown
This utility's overall score of 48/100 breaks down across five weighted components. Read the full methodology →
Contaminants detected — international standards comparison
Every contaminant detected, compared side-by-side against US EPA legal limits, the EU Drinking Water Directive (2020/2184), WHO Guidelines, and California's Public Health Goal (the strictest US benchmark). 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 |
55.8 ppb | 0.06 | — | — | — | — | — | 929× over |
| Haloacetic acids (HAA5) Disinfection byproduct |
41.0 ppb | 0.1 | 60.0 | 60 | — | — | — | 410× over |
| Trichloroacetic acid Disinfection byproduct |
26.7 ppb | 0.1 | — | — | — | — | — | 267× over |
| Total trihalomethanes (TTHMs) Disinfection byproduct |
30.2 ppb | 0.15 | 80.0 | 100 | — | — | — | 202× over |
| Dichloroacetic acid Disinfection byproduct |
13.3 ppb | 0.2 | — | — | — | — | — | 66× over |
| Chloroform Disinfection byproduct |
26.1 ppb | 0.4 | — | — | — | — | — | 65× over |
| Bromochloroacetic acid Disinfection byproduct |
1.06 ppb | 0.02 | — | — | — | — | — | 53× over |
| Bromodichloromethane Disinfection byproduct |
2.84 ppb | 0.06 | — | — | — | — | — | 47× over |
| Chromium (hexavalent) Heavy metal |
0.0568 ppb | 0.02 | — | — | — | — | — | 2.8× over |
| Nitrate and nitrite Inorganic |
0.141 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 1.0× over |
| Nitrate Inorganic |
0.14 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | Below guideline |
| Perfluorooctane sulfonate (PFOS) PFAS |
0.105 ppt | 0.3 | 4.0 | 100 | 100 | 1 | — | Below guideline |
| Manganese Heavy metal |
23.4 ppb | 100.0 | — | 50 | 80 | — | — | Below guideline |
| Dibromochloromethane Disinfection byproduct |
0.0231 ppb | 0.1 | — | — | — | — | — | Below guideline |
| Chlorate Disinfection byproduct |
6.42 ppb | 210.0 | — | — | — | — | — | Below guideline |
| Barium Heavy metal |
17.1 ppb | 700.0 | 2000.0 | — | 1300 | 2000 | — | Below guideline |
| Monochloroacetic acid Disinfection byproduct |
0.183 ppb | 53.0 | — | — | — | — | — | Below guideline |
| Vanadium Other |
0.0183 ppb | 21.0 | — | — | — | — | — | Below guideline |
| Strontium Radiological |
0.0211 ppb | 1500.0 | — | — | — | — | — | Below guideline |
| Chromium (total) Heavy metal |
0.174 ppb | — | 100.0 | — | — | — | — | Below guideline |
| Cyanide Inorganic |
3.89 ppb | — | 200.0 | 50 | 70 | 150 | — | Below guideline |
| Fluoride Inorganic |
0.597 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 (4th ed.), California OEHHA PHGs, EWG Tap Water Database.
WESTCHESTER JOINT WATER WORKS service area
This water system serves 1 community in Westchester County, New York. Click any city for its dedicated tap water quality page.
Find the right filter for MAMARONECK water
Browse filter categories by water-quality concern. Each option below is NSF-certified for the matched contaminant type.