Mamaroneck, NY water hardness

Tap water hardness
6mg/L
0.4gpg
Soft

Reported by Westchester Joint Water Works · October 2025

NY typical
31 mg/L
EPA health violations since 2016
3
Data
Utility report

Tap water in Mamaroneck has about 6 mg/L of hardness, which is 0.4 grains per gallon. On the USGS scale that counts as soft. The number comes from Westchester Joint Water Works, dated October 2025.

Mamaroneck on the hardness scale, with nearby cities
060120180240300360+NY typical 31Larchmont: 6 mg/LLarchmont 6New Rochelle: 6 mg/LNew Rochelle 6Scarsdale: 13 mg/LScarsdale 13Eastchester: 14 mg/LEastchester 14Tuckahoe: 14 mg/LTuckahoe 14Harrison: 17 mg/LHarrison 17White Plains: 21 mg/LWhite Plains 21Pelham: 22 mg/LPelham 22Pelham Manor: 24 mg/LPelham Manor 24Mount Vernon: 24 mg/LMount Vernon 24Mamaroneck 6mg/L as calcium carbonate060120180240300360+NY 31Larchmont: 6 mg/LLarchmont 6New Rochelle: 6 mg/LNew Rochel. 6Scarsdale: 13 mg/LScarsdale 13Eastchester: 14 mg/LEastchester 14Pelham: 22 mg/LPelham 22Pelham Manor: 24 mg/LPelham Man. 246 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

Mamaroneck sits 25 mg/L below the typical New York figure of 31. None of the 10 nearest cities we track has softer water. The range nearby runs from 6 mg/L in Larchmont to 24 in Pelham Manor.

What 6 mg/L means at home

Soap and shampoo lather with very little product. Kettles and showerheads stay mostly free of white crust.

Some people notice that soap feels slow to rinse off in soft water. That slippery feel is normal and harmless.

Hardness is not a health problem, and EPA sets no limit for it. It is a matter of scale and soap.

What to do about it

Nothing, as far as hardness goes. At 6 mg/L a softener would have almost nothing to remove.

Carbon filter

If the water tastes of chlorine, a pitcher or faucet carbon filter takes care of that. It does not change hardness.

EPA record for Mamaroneck's water system

Westchester Joint Water Works · PWSID NY5903435

3 health-based violations since 2016

Serves about 59,629 people from surface water.

Health-based
3
Monitoring or reporting
0
Open now
0
20162017201820192020202120222023202420252026Haloacetic acids (HAA5)'16'18'20'22'24'26Haloacetic acids (HAA5)
Each dot is one health-based violation, placed at the start of its compliance period.
Contaminant or ruleViolationsPeriodStatus
Haloacetic acids (HAA5)a disinfection byproduct32019Resolved

Health-based means a contaminant above its legal limit or a missed treatment step. Monitoring and reporting violations are late or missing tests and notices. Source: EPA ECHO, 2026Q3 export, violations with periods starting 2016 or later. Full EPA record.

Questions

Is Mamaroneck water hard?

No. It measures about 6 mg/L (0.4 grains per gallon), which the USGS classes as soft.

What is the water hardness in Mamaroneck in grains per gallon?

About 0.4 gpg. One grain per gallon equals 17.1 mg/L, so 6 mg/L divided by 17.1 gives 0.4.

Has the Mamaroneck water system had EPA violations?

EPA records show 3 health-based violations for Westchester Joint Water Works since 2016, involving Haloacetic acids (HAA5).

Nearby cities

All 149 cities in New York

Hardness data: TapWaterData US Water Hardness (utility report, October 7, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.