How hard is the water in Oskaloosa, IA?

Tap water hardness
110mg/L
6.4gpg
Moderately hard

Reported by Oskaloosa Municipal Water Dept · November 2024

IA typical
183 mg/L
EPA health violations since 2016
0
Softener for 3 people
24k grain
Data
Utility report

The water in Oskaloosa carries roughly 110 mg/L of dissolved calcium and magnesium, or 6.4 grains per gallon. That is moderately hard water. The number comes from Oskaloosa Municipal Water Dept, dated November 2024.

Oskaloosa on the hardness scale, with nearby cities
060120180240300360+IA typical 183North Liberty: 49 mg/LNorth Liberty 49Clive: 68 mg/LClive 68Iowa City: 76 mg/LIowa City 76Urbandale: 99 mg/LUrbandale 99Ankeny: 120 mg/LAnkeny 120Johnston: 126 mg/LJohnston 126Norwalk: 132 mg/LNorwalk 132West Des Moines: 135 mg/LWest Des Moines 135Altoona: 296 mg/LAltoona 296Des Moines: 296 mg/LDes Moines 296Oskaloosa 110mg/L as calcium carbonate060120180240300360+IA 183North Liberty: 49 mg/LNorth Libe. 49Ankeny: 120 mg/LAnkeny 120Norwalk: 132 mg/LNorwalk 132West Des Moines: 135 mg/LWest Des M. 135Altoona: 296 mg/LAltoona 296Des Moines: 296 mg/LDes Moines 296110 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 110 mg/L, Oskaloosa is 73 mg/L below the typical Iowa figure of 183. Of the 10 nearest cities we track, 4 have softer water and 6 have harder. The range nearby runs from 49 mg/L in North Liberty to 296 in Altoona.

What 110 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 Oskaloosa

3 people × 75 gallons a day × 6.4 gpg = 1,447 grains a day. A 24,000-grain unit regenerates about every 16 days.

Size it for your household

EPA record for Oskaloosa's water system

Oskaloosa Municipal Water Dept · PWSID IA6273005

No health-based violations since 2016

Serves about 12,808 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 Oskaloosa water hard?

Somewhat. It measures about 110 mg/L (6.4 grains per gallon), which the USGS classes as moderately hard.

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

About 6.4 gpg. One grain per gallon equals 17.1 mg/L, so 110 mg/L divided by 17.1 gives 6.4.

What size water softener do I need in Oskaloosa?

For 3 people using 75 gallons each per day, 6.4 gpg works out to about 1,447 grains a day. A 24,000-grain softener covers that with a regeneration about every 16 days.

Has the Oskaloosa water system had EPA violations?

EPA records show no health-based violations for Oskaloosa Municipal Water Dept since 2016. There were also 3 monitoring or reporting violations, which are about late or missing tests and notices.

Nearby cities

All 25 cities in Iowa

Hardness data: TapWaterData US Water Hardness (utility report, November 19, 2024), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.