State water index

Iowa water hardness

Search 685 indexed communities and 723 ZIP profiles, then compare the underlying utility, source, distance, and reporting context.

Median regional evidence

281PPM

Very Hard

Indexed range 101–729.5 PPM

ZIP profiles: 723
Cities: 685
Matched utilities: 938
Counties: 99

Understanding Iowa

Why local comparisons matter here

Iowa systems draw from rivers, alluvial aquifers, glacial deposits, and deeper bedrock units. Treatment and source blending can matter as much as distance.

In this index, very hard is the largest category, covering 420 of 443 profiles with hardness data. The state median is 281 PPM, but the full indexed range is 101–729.5 PPM.

State distribution

Hardness across indexed ZIPs

Counts describe published ZIP profiles, not a population-weighted statewide sample.

Soft · 0–60 PPM0

Moderately hard · 61–120 PPM2

Hard · 121–180 PPM21

Very hard · 181+ PPM420

Evidence coverage

What the current records support

Hardness estimate: 61%
Lead 90th percentile: 100%
Copper 90th percentile: 19%

296

Low-confidence hardness profiles

Research-comparison eligible profiles

Reported source water

Utility source mix

Groundwater: 788
Surface water: 124
Groundwater influenced by surface water: 26

Highest medians

Highest eligible city medians

1. Cedar Rapids274 PPM

Lowest medians

Lowest eligible city medians

1. Cedar Rapids274 PPM

City directory

Explore Iowa by city

Search by city or county, then sort by name, hardness, or ZIP coverage.

685 cities · 723 ZIP profiles

Search city or county

County

Sort by

685 cities found

Page 1 of 29

Ackley

Franklin County · 1 ZIP

251PPM regional

County	Median	Range	ZIP profiles
Harrison County	453 PPM	381–506	8
Plymouth County	449 PPM	449–596	9
Woodbury County	414 PPM	367.5–449	13
Pottawattamie County	412 PPM	239.5–693	12
Dallas County	389 PPM	376–401	11
Monona County	386 PPM	367.5–409	8
Fremont County	385 PPM	288.5–729.5	7
Polk County	376 PPM	351–376	28
Story County	376 PPM	351–376	14
Boone County	376 PPM	376–401	6
Marshall County	359 PPM	310.5–367	10
Allamakee County	337 PPM	296–337	5

Why local comparisons matter here

Hardness across indexed ZIPs

What the current records support

Utility source mix

Highest eligible city medians

Lowest eligible city medians

Explore Iowa by city

Ackley

Adair

Adel

Agency

Ainsworth

Akron

Albia

Albion

Alburnett

Alden

Alexander

Algona

Allerton

Allison

Alta

Alta Vista

Alton

Altoona

Alvord

Amana

Ames

Anamosa

Andover

Andrew

Highest regional-evidence county medians