How hard is the water in Ossining, NY?

Tap water hardness
103mg/L
6.0gpg
Moderately hard

Reported by Ossining Water Department · August 2025

NY typical
31 mg/L
EPA health violations since 2016
0
Softener for 3 people
24k grain
Data
Utility report

The water in Ossining carries roughly 103 mg/L of dissolved calcium and magnesium, or 6.0 grains per gallon. That is moderately hard water. The number comes from Ossining Water Department, dated August 2025.

Ossining on the hardness scale, with nearby cities
060120180240300360+NY typical 31Irvington: 6 mg/LIrvington 6Elmsford: 17 mg/LElmsford 17Tarrytown: 19 mg/LTarrytown 19Sleepy Hollow: 22 mg/LSleepy Hollow 22Briarcliff Manor: 30 mg/LBriarcliff Manor 30Pleasantville: 32 mg/LPleasantville 32Mount Kisco: 55 mg/LMount Kisco 55New City: 106 mg/LNew City 106Spring Valley: 106 mg/LSpring Valley 106Croton-on-Hudson: 107 mg/LCroton-on-Hudson 107Ossining 103mg/L as calcium carbonate060120180240300360+NY 31Tarrytown: 19 mg/LTarrytown 19Sleepy Hollow: 22 mg/LSleepy Hol. 22Briarcliff Manor: 30 mg/LBriarcliff. 30Pleasantville: 32 mg/LPleasantvi. 32New City: 106 mg/LNew City 106Croton-on-Hudson: 107 mg/LCroton-on-. 107103 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

At 103 mg/L, Ossining is 72 mg/L above the typical New York figure of 31. Of the 10 nearest cities we track, 7 have softer water and 3 have harder. The range nearby runs from 6 mg/L in Irvington to 107 in Croton-on-Hudson.

What 103 mg/L means at home

You may see faint white spots on glasses and shower doors after the water dries.

Scale builds up slowly. A kettle or coffee maker needs descaling now and then, maybe every few months.

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

Optional. Plenty of households at this level live with it and descale the kettle now and then.

Water softener

Worth a look if spots on glass bother you, or if your tankless water heater manual asks for softer water.

Carbon filter

Improves taste and removes chlorine. It leaves calcium and magnesium in place.

Softener size for Ossining

3 people × 75 gallons a day × 6.0 gpg = 1,354 grains a day. A 24,000-grain unit regenerates about every 17 days.

Size it for your household

EPA record for Ossining's water system

Ossining Water Department · PWSID NY5903451

No health-based violations since 2016

Serves about 30,000 people from surface water.

Health-based
0
Monitoring or reporting
2
Open now
0

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 Ossining water hard?

Somewhat. It measures about 103 mg/L (6.0 grains per gallon), which the USGS classes as moderately hard.

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

About 6.0 gpg. One grain per gallon equals 17.1 mg/L, so 103 mg/L divided by 17.1 gives 6.0.

What size water softener do I need in Ossining?

For 3 people using 75 gallons each per day, 6.0 gpg works out to about 1,354 grains a day. A 24,000-grain softener covers that with a regeneration about every 17 days.

Has the Ossining water system had EPA violations?

EPA records show no health-based violations for Ossining Water Department since 2016. There were also 2 monitoring or reporting violations, which are about late or missing tests and notices.

Nearby cities

All 149 cities in New York

Hardness data: TapWaterData US Water Hardness (utility report, August 10, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.