Groton, CT water hardness

Tap water hardness
22mg/L
1.3gpg
Soft

Reported by Groton Utilities · August 2025

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

The water in Groton carries roughly 22 mg/L of dissolved calcium and magnesium, or 1.3 grains per gallon. That is soft water. The number comes from Groton Utilities, dated August 2025.

Groton on the hardness scale, with nearby cities
060120180240300360+CT typical 53Glastonbury Center: 16 mg/LGlastonbury Center 16Wethersfield: 16 mg/LWethersfield 16East Hartford: 16 mg/LEast Hartford 16New London: 21 mg/LNew London 21Conning Towers-Nautilus Park: 22 mg/LConning Towers-Nautilus Park 22Northford: 46 mg/LNorthford 46Branford Center: 46 mg/LBranford Center 46Middletown: 64 mg/LMiddletown 64Storrs: 97 mg/LStorrs 97Manchester: 131 mg/LManchester 131Groton 22mg/L as calcium carbonate060120180240300360+CT 53Glastonbury Center: 16 mg/LGlastonbur. 16New London: 21 mg/LNew London 21Conning Towers-Nautilus Park: 22 mg/LConning To. 22Northford: 46 mg/LNorthford 46Middletown: 64 mg/LMiddletown 64Storrs: 97 mg/LStorrs 9722 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 22 mg/L, Groton is 31 mg/L below the typical Connecticut figure of 53. Of the 10 nearest cities we track, 4 have softer water and 5 have harder. The range nearby runs from 16 mg/L in Glastonbury Center to 131 in Manchester.

What 22 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 22 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 Groton's water system

Groton Utilities · PWSID CT0590011

No health-based violations since 2016

Serves about 30,200 people from surface water.

Health-based
0
Monitoring or reporting
3
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 Groton water hard?

No. It measures about 22 mg/L (1.3 grains per gallon), which the USGS classes as soft.

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

About 1.3 gpg. One grain per gallon equals 17.1 mg/L, so 22 mg/L divided by 17.1 gives 1.3.

Has the Groton water system had EPA violations?

EPA records show no health-based violations for Groton Utilities since 2016. There were also 3 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, August 1, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.