Greenwich, CT water hardness

Tap water hardness
53mg/L
3.1gpg
Soft

Reported by Aquarion Water CO of CT-Main System · October 2025

CT typical
53 mg/L
EPA health violations since 2016
0
Data
Utility report

Greenwich water measures 53 mg/L (3.1 gpg) of hardness, soft by USGS standards. The number comes from Aquarion Water CO of CT-Main System, dated October 2025.

Greenwich on the hardness scale, with nearby cities
060120180240300360+CT typical 53Riverside: 53 mg/LRiverside 53Cos Cob: 53 mg/LCos Cob 53Byram: 53 mg/LByram 53Old Greenwich: 53 mg/LOld Greenwich 53Stamford: 53 mg/LStamford 53Noroton: 53 mg/LNoroton 53New Canaan: 53 mg/LNew Canaan 53Norwalk: 53 mg/LNorwalk 53Staples: 53 mg/LStaples 53Ridgefield: 53 mg/LRidgefield 53Greenwich 53mg/L as calcium carbonate060120180240300360+CT 53Riverside: 53 mg/LRiverside 53Cos Cob: 53 mg/LCos Cob 53Byram: 53 mg/LByram 53Old Greenwich: 53 mg/LOld Greenw. 53Stamford: 53 mg/LStamford 53Noroton: 53 mg/LNoroton 5353 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 53 mg/L, Greenwich is close to the typical Connecticut figure of 53 mg/L. None of the 10 nearest cities we track has harder water.

What 53 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 53 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 Greenwich's water system

Aquarion-Eastern Fairfield County · PWSID CT0150011

No health-based violations since 2016

Serves about 351,756 people from surface water.

Health-based
0
Monitoring or reporting
152
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 Greenwich water hard?

No. It measures about 53 mg/L (3.1 grains per gallon), which the USGS classes as soft.

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

About 3.1 gpg. One grain per gallon equals 17.1 mg/L, so 53 mg/L divided by 17.1 gives 3.1.

Has the Greenwich water system had EPA violations?

EPA records show no health-based violations for Aquarion-Eastern Fairfield County since 2016. There were also 152 monitoring or reporting violations, which are about late or missing tests and notices.

Nearby cities

All 51 cities in Connecticut

Hardness data: TapWaterData US Water Hardness (utility report, October 8, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.