Is Mamaroneck, NY tap water safe?
Supplied by Westchester Joint Water Works · serves 59,629 people (12,000 connections) · Surface water · EPA ID NY5903435
Data: U.S. EPA · How we read the data · How we check it
Buys water from New York City System. Treated water bought from another system can carry that system's contaminants.
Summary
No federal limits exceeded in EPA data.
- PFAS
- Not detectedNone of 29 PFAS found above EPA's reporting limits in 8 samples (2023–2025).
- Lead
- Below action level3 ppb (parts per billion) at the 90th percentile: 9 in 10 homes sampled were at or below it. Action level 15 ppb, falling to 10 ppb in Nov 2027. Monitoring period Jan 2026 – now, still in progress (results reported so far). Your home's pipes can make yours higher.
- Violations
- Resolved3 health-based violations since 2016, most recently Jul 2019.
- Built before 1986, or not sure what your service line is made of? Check your service line and test your tap. Utility data can't show your pipes.
- Want to reduce what was found? Filters for these results.
- Tested your own tap? Compare your result with these numbers. Moving? Compare this system with another.
- Read Westchester Joint Water Works's annual water quality report (Consumer Confidence Report). It lists every regulated contaminant tested and is usually on the utility's website or mailed with your bill, and you can also request it at (914) 777-7722. EPA: how to find it.
PFAS (“forever chemicals”)
EPA UCMR 5: 2 entry points tested Feb 2025 to Nov 2025. "Average" is the highest entry-point average (non-detects counted as zero), the way EPA compares UCMR 5 results to the limits. ppt = parts per trillion. These results do not determine compliance.
| Contaminant | Highest average |
|---|---|
| PFOA Not detected Limit 4 ppt | – |
| PFOS Not detected Limit 4 ppt | – |
| PFHxS Not detected Limit 10 ppt | – |
| PFNA Not detected Limit 10 ppt | – |
| HFPO-DA (GenX) Not detected Limit 10 ppt | – |
| Hazard Index (a combined score for PFHxS, PFNA, GenX and PFBS, where above 1 is over the limit) Not detected Limit 1 | – |
| PFBS Not detected Guideline 2,000 ppt | – |
| PFBA Not detected Guideline 6,000 ppt | – |
| PFHxA Not detected Guideline 3,000 ppt | – |
New York has its own PFAS limits. PFOA 10 ppt (this system's highest average: not detected), PFOS 10 ppt (this system's highest average: not detected). State compliance is judged on the state's own sampling, so ask the utility or the state program whether it meets them.
29 PFAS tested, 0 detected at least once. "Not detected" means below EPA's reporting limit (about 2 to 20 ppt depending on the chemical), not proven zero. PFAS not listed were not detected. The limits for PFHxS, PFNA, GenX and the Hazard Index were proposed for rescission in May 2026. That proposal is not final. Systems have until 2029 to meet the limits.
Lithium
Not detected in 8 samples (reporting limit 9 ppb). About lithium.
Lead and copper
Latest 90th percentile: 3 ppb lead (Jan 2026 – now (in progress)). Below action level
Highest since 2016: 10.7 ppb (Dec 2021).
| Monitoring period | Lead (90th pct.) |
|---|---|
| Jan 2026 – now (in progress) | 3 ppb |
| Jan 2025 – now (in progress) | 3 ppb |
| Jan 2024 – now (in progress) | 4.5 ppb |
Earlier results (9)
| Jan 2023 – Dec 2025 | 3.3 ppb |
| Jan 2020 – Dec 2022 | 8.1 ppb |
| Jan 2019 – Dec 2021 | 10.7 ppb |
| Jan 2018 – Dec 2020 | 10.7 ppb |
| Jan 2019 – Dec 2019 | 10.7 ppb |
| Jan 2018 – Dec 2018 | 4.8 ppb |
| Jan 2017 – Dec 2017 | 3.9 ppb |
| Jan 2016 – Dec 2016 | 4.4 ppb |
| Jan 2015 – Dec 2015 | 2.5 ppb |
Copper 90th percentile: 1.63 ppm (Dec 1992), action level 1,300 ppb.
Lead comes from pipes and fixtures, not the source water, so it varies home to home. The 90th percentile means 9 in 10 sampled homes were at or below it. More on lead.
Violations
| When | What happened |
|---|---|
| Jan 2019 – Jul 2019 3 times | The running annual average for Total Haloacetic Acids (HAA5) was above the legal limit. EPA record: Total Haloacetic Acids (HAA5) · Maximum Contaminant Level Violation, Average · measured 0.061 mg/l (limit 0.060 mg/L) Resolved |
Health-based violations mean a contaminant exceeded a limit or a required treatment step was missed. Monitoring and reporting violations mean required tests or reports were late or missing, so the water's quality during that time is unknown. The total includes every violation in EPA's records, most of them paperwork.
Earlier EPA testing (2013–2020)
| Contaminant | Highest | Guideline |
|---|---|---|
| Manganese | 126 ppb | 300 ppb |
| Vanadium | 0.22 ppb | 21 ppb |
| Strontium | 0.026 ppm | 1.5 ppm |
| Chromium-6 | 0.094 ppb | – |
| Chlorate | 31 ppb | 210 ppb |
Where it serves
Mamaroneck, Harrison
ZIP codes the system reported serving: 10528, 10538, 10543, 10577, 10604
Nearby utilities
- Veolia Water New York, Inc. Rd-1 New Rochelle · 2 mi
- Veolia Water New York, Inc. Rd-2 Rye · 3 mi · PFAS above limit
- Mount Vernon Water Department Mount Vernon · 4 mi
- Glen Cove City Water System Glen Cove · 6 mi · PFAS above limit
- City of Yonkers Yonkers · 7 mi
- White Plains City Water System White Plains · 7 mi
Questions
Is Mamaroneck tap water safe to drink?
Most of Mamaroneck gets its water from Westchester Joint Water Works. Westchester Joint Water Works had 3 health-based violations since 2016, all since resolved. EPA testing found no PFAS above the federal limits. Federal data can't tell you about your own pipes: lead comes from service lines and plumbing, so test your tap if your home was built before 1986. For the official word, read the utility's annual Consumer Confidence Report.
Does Mamaroneck water have PFAS?
EPA tested Westchester Joint Water Works for 29 PFAS between Feb 2025 and Nov 2025 and none were detected above the reporting limits (about 2 to 20 ppt depending on the chemical).
What is the lead level in Mamaroneck water?
The most recent 90th-percentile lead result for Westchester Joint Water Works is 3 ppb, for the monitoring period that began Jan 2026 (still in progress). The federal action level is 15 ppb, falling to 10 ppb in November 2027. The 90th percentile means 9 in 10 homes sampled were at or below this number. Individual homes can be higher.
Check these numbers yourself
Every figure on this page comes from public EPA records. You don't have to take our word for it:
- EPA's own report for NY5903435: violations, enforcement and inspections, straight from EPA.
- EPA UCMR 5 data: the PFAS and lithium results (search the file for PWSID NY5903435).
- EPA SDWIS download: the lead results, population and violation records we use.
- The utility's annual water quality report (Consumer Confidence Report): ask Westchester Joint Water Works at (914) 777-7722, or see EPA's guide to finding it.
Found something that doesn't match? Tell us and we'll check it against EPA's records. How we check our data.
Source: U.S. EPA drinking water records and PFAS testing (UCMR 5). How we read the data.