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 indexed hardness

281PPM

Very Hard

Indexed range 182–834 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 721 of 721 profiles with hardness data. The state median is 281 PPM, but the full indexed range is 182–834 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 PPM0

Hard · 121–180 PPM0

Very hard · 181+ PPM721

Evidence coverage

What the current records support

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

284

Low-confidence hardness profiles

282

Nearest site more than 25 miles away

Reported source water

Utility source mix

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

Highest medians

Hardest indexed cities

1. Lester834 PPM
2. Rock Rapids834 PPM
3. Larchwood747 PPM
4. Adair522 PPM
5. Alvord522 PPM

Lowest medians

Softest indexed cities

1. Lineville182 PPM
2. Seymour191 PPM
3. Mystic191 PPM
4. Leon191 PPM
5. Humeston191 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

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685 cities found

Page 1 of 29

Ackley

Franklin County · 1 ZIP

275PPM

County	Median	Range	ZIP profiles
Lyon County	515 PPM	419–834	8
Guthrie County	506 PPM	322–522	7
Sioux County	461 PPM	419–465	11
Plymouth County	457 PPM	443–464	9
Clay County	449 PPM	321–449	5
O'Brien County	434 PPM	409–449	7
Woodbury County	430 PPM	411.5–456.5	13
Carroll County	425 PPM	376–472	11
Polk County	421 PPM	291–420.5	28
Boone County	421 PPM	327–420.5	6
Sac County	420 PPM	376–434.5	6
Osceola County	419 PPM	419–449	5

Why local comparisons matter here

Hardness across indexed ZIPs

What the current records support

Utility source mix

Hardest indexed cities

Softest indexed cities

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 indexed county medians