How hard is the water in St. Paul, MN?

Tap water hardness
82mg/L
4.8gpg
Moderately hard

Reported by Saint Paul Regional Water Services · August 2025

MN typical
160 mg/L
EPA health violations since 2016
1
Softener for 3 people
24k grain
Data
Utility report

St. Paul water measures 82 mg/L (4.8 gpg) of hardness, moderately hard by USGS standards. The number comes from Saint Paul Regional Water Services, dated August 2025.

St. Paul on the hardness scale, with nearby cities
060120180240300360+MN typical 160Maplewood: 56 mg/LMaplewood 56North St. Paul: 56 mg/LNorth St. Paul 56Roseville: 78 mg/LRoseville 78Minneapolis: 89 mg/LMinneapolis 89Eagan: 132 mg/LEagan 132Woodbury: 160 mg/LWoodbury 160Shoreview: 192 mg/LShoreview 192New Brighton: 230 mg/LNew Brighton 230St. Anthony: 254 mg/LSt. Anthony 254Inver Grove Heights: 270 mg/LInver Grove Heights 270St. Paul 82mg/L as calcium carbonate060120180240300360+MN 160Maplewood: 56 mg/LMaplewood 56North St. Paul: 56 mg/LNorth St.. 56Roseville: 78 mg/LRoseville 78Minneapolis: 89 mg/LMinneapolis 89St. Anthony: 254 mg/LSt. Anthony 254Inver Grove Heights: 270 mg/LInver Grov. 27082 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

St. Paul sits 78 mg/L below the typical Minnesota figure of 160. Of the 10 nearest cities we track, 3 have softer water and 7 have harder. The range nearby runs from 56 mg/L in Maplewood to 270 in Inver Grove Heights.

What 82 mg/L means at home

You may see faint white spots on glasses and shower doors after the water dries.

Scale builds up slowly. A kettle or coffee maker needs descaling now and then, maybe every few months.

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

Optional. Plenty of households at this level live with it and descale the kettle now and then.

Water softener

Worth a look if spots on glass bother you, or if your tankless water heater manual asks for softer water.

Carbon filter

Improves taste and removes chlorine. It leaves calcium and magnesium in place.

Softener size for St. Paul

3 people × 75 gallons a day × 4.8 gpg = 1,080 grains a day. A 24,000-grain unit regenerates about every 22 days.

Size it for your household

EPA record for St. Paul's water system

Saint Paul Regional Water Services · PWSID MN1620026

1 health-based violation since 2016

Serves about 392,529 people from surface water.

Health-based
1
Monitoring or reporting
10
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 sampling12022Resolved

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 St. Paul water hard?

Somewhat. It measures about 82 mg/L (4.8 grains per gallon), which the USGS classes as moderately hard.

What is the water hardness in St. Paul in grains per gallon?

About 4.8 gpg. One grain per gallon equals 17.1 mg/L, so 82 mg/L divided by 17.1 gives 4.8.

What size water softener do I need in St. Paul?

For 3 people using 75 gallons each per day, 4.8 gpg works out to about 1,080 grains a day. A 24,000-grain softener covers that with a regeneration about every 22 days.

Has the St. Paul water system had EPA violations?

EPA records show 1 health-based violation for Saint Paul Regional Water Services since 2016, involving Lead and Copper Rule. There were also 10 monitoring or reporting violations, which are about late or missing tests and notices.

Nearby cities

All 57 cities in Minnesota

Hardness data: TapWaterData US Water Hardness (utility report, August 13, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.