Hard water in Polk City, IA
Reported by Polk City Water Supply · March 2025
- IA typical
- 183 mg/L
- EPA health violations since 2016
- 0
- Softener for 3 people
- 24k grain
- Data
- Utility report
Tap water in Polk City has about 151 mg/L of hardness, which is 8.8 grains per gallon. On the USGS scale that counts as hard. The number comes from Polk City Water Supply, dated March 2025.
Polk City sits 32 mg/L below the typical Iowa figure of 183. Of the 10 nearest cities we track, 7 have softer water and 3 have harder. The range nearby runs from 68 mg/L in Clive to 302 in Waukee.
What 151 mg/L means at home
Expect white crust on faucets and showerheads, plus spots on dishes that come out of the dishwasher.
Kettles collect scale quickly. Water heaters build up sediment at the bottom of the tank, which makes them work harder over time.
Soap and detergent need a little more to lather, and soap scum shows up in the tub.
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
At 151 mg/L most of the trouble is scale, and only a few things deal with it.
Ion-exchange water softener
The standard whole-house fix. It swaps calcium and magnesium for sodium or potassium and needs salt plus a drain. Size it with the calculator below.
Salt-free conditioner
No salt and no drain line. It changes how minerals form scale instead of removing them, so water still tests hard.
Reverse osmosis or carbon filter
Under-sink reverse osmosis removes minerals from drinking water only. Plain carbon filters improve taste but do not soften.
3 people × 75 gallons a day × 8.8 gpg = 1,987 grains a day. A 24,000-grain unit regenerates about every 12 days.
EPA record for Polk City's water system
No health-based violations since 2016
Serves about 6,533 people from surface water.
- Health-based
- 0
- Monitoring or reporting
- 0
- 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 Polk City water hard?
Yes. It measures about 151 mg/L (8.8 grains per gallon), which the USGS classes as hard.
What is the water hardness in Polk City in grains per gallon?
About 8.8 gpg. One grain per gallon equals 17.1 mg/L, so 151 mg/L divided by 17.1 gives 8.8.
What size water softener do I need in Polk City?
For 3 people using 75 gallons each per day, 8.8 gpg works out to about 1,987 grains a day. A 24,000-grain softener covers that with a regeneration about every 12 days.
Has the Polk City water system had EPA violations?
EPA records show no health-based violations for Polk City Water Supply since 2016.
Nearby cities
- Johnston126 mg/LHard
- Ankeny120 mg/LModerately hard
- Urbandale99 mg/LModerately hard
- Clive68 mg/LModerately hard
- Altoona296 mg/LVery hard
- Des Moines296 mg/LVery hard
- Waukee302 mg/LVery hard
- West Des Moines135 mg/LHard
- Ames150 mg/LHard
- Norwalk132 mg/LHard
Hardness data: TapWaterData US Water Hardness (utility report, March 13, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.