Arlington, MA water hardness

Tap water hardness
17mg/L
1.0gpg
Soft

Reported by Arlington Water Dept. (MWRA) · August 2025

MA typical
38 mg/L
EPA health violations since 2016
0
Data
Utility report

The water in Arlington carries roughly 17 mg/L of dissolved calcium and magnesium, or 1.0 grains per gallon. That is soft water. The number comes from Arlington Water Dept. (MWRA), dated August 2025.

Arlington on the hardness scale, with nearby cities
060120180240300360+MA typical 38Belmont: 16 mg/LBelmont 16Watertown: 16 mg/LWatertown 16Stoneham: 16 mg/LStoneham 16Waltham: 17 mg/LWaltham 17Winchester: 20 mg/LWinchester 20Somerville: 20 mg/LSomerville 20Medford: 21 mg/LMedford 21Lexington: 33 mg/LLexington 33Cambridge: 60 mg/LCambridge 60Woburn: 99 mg/LWoburn 99Arlington 17mg/L as calcium carbonate060120180240300360+MA 38Belmont: 16 mg/LBelmont 16Watertown: 16 mg/LWatertown 16Winchester: 20 mg/LWinchester 20Somerville: 20 mg/LSomerville 20Medford: 21 mg/LMedford 21Cambridge: 60 mg/LCambridge 6017 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, Arlington is 21 mg/L below the typical Massachusetts figure of 38. Of the 10 nearest cities we track, 3 have softer water and 6 have harder. The range nearby runs from 16 mg/L in Belmont to 99 in Woburn.

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 Arlington's water system

Arlington Water Dept. (MWRA) · PWSID MA3010000

No health-based violations since 2016

Serves about 46,308 people from surface water.

Health-based
0
Monitoring or reporting
1
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 Arlington 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 Arlington 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 Arlington water system had EPA violations?

EPA records show no health-based violations for Arlington Water Dept. (MWRA) since 2016. There were also 1 monitoring or reporting violation, which are about late or missing tests and notices.

Nearby cities

All 104 cities in Massachusetts

Hardness data: TapWaterData US Water Hardness (utility report, August 4, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.