Rochester, NH water hardness

Tap water hardness
20mg/L
1.1gpg
SoftCounty estimate

County estimate from 142 water samples in Strafford County · July 2026

NH typical
20 mg/L
EPA health violations since 2016
3
Data
County estimate

Water samples from around Rochester put hardness at about 20 mg/L (1.1 gpg), which would be soft on the USGS scale. Treat this as a rough guide: it is the median of 142 samples taken across Strafford County, mostly wells and streams, not a test of Rochester's treated tap water. One more reason for caution: EPA lists Rochester's water system as using surface water, which is often softer than the wells behind the county figure.

Rochester on the hardness scale, with nearby cities
060120180240300360+NH typical 20Concord: 13 mg/LConcord 13Keene: 15 mg/LKeene 15Manchester: 16 mg/LManchester 16Lebanon: 22 mg/LLebanon 22Hudson: 31 mg/LHudson 31Nashua: 31 mg/LNashua 31Dover: 64 mg/LDover 64Portsmouth: 123 mg/LPortsmouth 123Derry: 123 mg/LDerry 123Rochester 20mg/L as calcium carbonate060120180240300360+NH 20Concord: 13 mg/LConcord 13Manchester: 16 mg/LManchester 16Hudson: 31 mg/LHudson 31Dover: 64 mg/LDover 64Portsmouth: 123 mg/LPortsmouth 123Derry: 123 mg/LDerry 12320 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

Rochester sits close to the typical New Hampshire figure of 20 mg/L. Of the 9 nearest cities we track, 3 have softer water and 6 have harder. The range nearby runs from 13 mg/L in Concord to 123 in Portsmouth.

What 20 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 20 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 Rochester's water system

Rochester Water Dept · PWSID NH2001010

3 health-based violations since 2016

Serves about 25,000 people from surface water.

Health-based
3
Monitoring or reporting
2
Open now
2

EPA lists this system as serving Rochester.

20162017201820192020202120222023202420252026Haloacetic acids (HAA5)Total trihalomethanes (TTHM)'16'18'20'22'24'26Haloacetic acids (HAA5)Total trihalomethanes (TTHM)
Each dot is one health-based violation, placed at the start of its compliance period.
Contaminant or ruleViolationsPeriodStatus
Haloacetic acids (HAA5)a disinfection byproduct12022Resolved
Total trihalomethanes (TTHM)a disinfection byproduct22016Resolved

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 Rochester water hard?

No. It measures about 20 mg/L (1.1 grains per gallon), which the USGS classes as soft.

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

About 1.1 gpg. One grain per gallon equals 17.1 mg/L, so 20 mg/L divided by 17.1 gives 1.1.

Has the Rochester water system had EPA violations?

EPA records show 3 health-based violations for Rochester Water Dept since 2016, involving Haloacetic acids (HAA5), Total trihalomethanes (TTHM). There were also 2 monitoring or reporting violations, which are about late or missing tests and notices.

Nearby cities

All 10 cities in New Hampshire

Hardness data: TapWaterData US Water Hardness (county estimate, July 4, 2026), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.