Boston, MA water hardness

Tap water hardness
17mg/L
1.0gpg
Soft

Reported by Boston Water and Sewer Commission (MWRA) · September 2025

MA typical
38 mg/L
EPA health violations since 2016
1
Data
Utility report

Boston water measures 17 mg/L (1.0 gpg) of hardness, soft by USGS standards. The number comes from Boston Water and Sewer Commission (MWRA), dated September 2025.

Boston on the hardness scale, with nearby cities
060120180240300360+MA typical 38Chelsea: 16 mg/LChelsea 16Everett: 16 mg/LEverett 16Brookline: 19 mg/LBrookline 19Somerville: 20 mg/LSomerville 20Medford: 21 mg/LMedford 21Malden: 25 mg/LMalden 25Quincy: 38 mg/LQuincy 38Milton: 44 mg/LMilton 44Cambridge: 60 mg/LCambridge 60Revere: 87 mg/LRevere 87Boston 17mg/L as calcium carbonate060120180240300360+MA 38Chelsea: 16 mg/LChelsea 16Everett: 16 mg/LEverett 16Somerville: 20 mg/LSomerville 20Quincy: 38 mg/LQuincy 38Cambridge: 60 mg/LCambridge 60Revere: 87 mg/LRevere 8717 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 17 mg/L, Boston is 21 mg/L below the typical Massachusetts figure of 38. Of the 10 nearest cities we track, 2 have softer water and 8 have harder. The range nearby runs from 16 mg/L in Chelsea to 87 in Revere.

What 17 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 17 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 Boston's water system

Boston Water and Sewer Commission (MWRA) · PWSID MA3035000

1 health-based violation since 2016

Serves about 675,647 people from surface water.

Health-based
1
Monitoring or reporting
0
Open now
0
20162017201820192020202120222023202420252026Lead and Copper Rule'16'18'20'22'24'26Lead and Copper Rule
Each dot is one health-based violation, placed at the start of its compliance period.
Contaminant or ruleViolationsPeriodStatus
Lead and Copper Rulecorrosion control and lead sampling12020Resolved

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 Boston water hard?

No. It measures about 17 mg/L (1.0 grains per gallon), which the USGS classes as soft.

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

About 1.0 gpg. One grain per gallon equals 17.1 mg/L, so 17 mg/L divided by 17.1 gives 1.0.

Has the Boston water system had EPA violations?

EPA records show 1 health-based violation for Boston Water and Sewer Commission (MWRA) since 2016, involving Lead and Copper Rule.

Nearby cities

All 104 cities in Massachusetts

Hardness data: TapWaterData US Water Hardness (utility report, September 23, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.