Water hardness by state
How hard is the water in Iowa?
Tap water in Iowa averages 20.5 grains per gallon (351 ppm calcium carbonate). That number determines how fast limescale coats your water heater, shower glass and appliances.
Sur la base de 1 001 mesures issues de 381 points de surveillance, 2005-01 → 2023-06.
Dureté de l’eau par comté — Iowa
Médianes des mesures relevées dans chaque comté. La dureté varie beaucoup plus à l’intérieur d’un État qu’entre États voisins : c’est de là que vient réellement votre valeur.
| Comté | gpg | mg/L | Fourchette (mg/L) | Classification |
|---|---|---|---|---|
| Linn County | 15.7 | 268 | 229–320 | Hard water |
| Hardin County | 21.5 | 367 | 325–427 | Very hard water |
| Hamilton County | 24.2 | 414 | 311–562 | Very hard water |
| Muscatine County | 13.9 | 238 | 145–330 | Moderately hard water |
| Benton County | 17.1 | 292 | 165–350 | Hard water |
| Johnson County | 19.7 | 337 | 212–444 | Hard water |
| Black Hawk County | 15 | 256 | 184–350 | Hard water |
| Iowa County | 19.9 | 340 | 164–440 | Hard water |
| Poweshiek County | 22.2 | 380 | 165–465 | Very hard water |
| Tama County | 20.5 | 350 | 257–444 | Very hard water |
| Washington County | 18.3 | 313 | 146–360 | Hard water |
| Hancock County | 21.1 | 360 | 271–440 | Very hard water |
La fourchette correspond aux 10e-90e centiles des mesures locales. Les comtés comptant moins de cinq mesures sont omis plutôt qu’estimés.
What 20.5 gpg means in Iowa
This is very hard water — among the harshest levels measured. Scale attacks water heaters, dishwashers and pipes fast, shortening appliance lifespan and inflating energy bills. Protection is essential.
What it does to your home
Water heater: even a thin layer of scale insulates the heating element and drives energy use up.
Appliances: dishwashers, washing machines and coffee makers scale up and fail years early.
Fixtures and skin: white spots on faucets and glass, dry skin and dull hair after every shower.
Comment cette valeur a été obtenue
Median of the site-level medians at 381 groundwater monitoring sites (wells and springs — the sources most US public systems draw from) in the USGS National Water Information System (1,001 individual measurements, 2005-01 → 2023-06). Each site is collapsed to one value first so that a heavily sampled location cannot skew the state figure; the range shown is the 10th-90th percentile across sites. This describes the raw water resource, not a specific municipal tap after treatment.
Water Quality Portal — USGS National Water Information System (NWIS), characteristic "Hardness, Ca, Mg"Statewide average — hardness varies by utility and season. Always verify with your local water quality report.
Frequently asked questions — Iowa
Is 20.5 gpg considered hard water?
On the US scale, 0–3.5 gpg is soft, 3.5–7 gpg moderately hard, 7–10.5 gpg hard and above 10.5 gpg very hard. At 20.5 gpg (351 ppm), water in Iowa is classified as Very hard water.
Does Iowa have a limescale problem?
Water in Iowa averages 20.5 gpg — Very hard water. The harder the water, the faster calcium carbonate deposits build up in water heaters, appliances and pipes. Below 3.5 gpg the risk is minimal; above 7 gpg scale becomes a running cost.
How do I find the exact water hardness at my address in Iowa?
Check your utility's annual water quality report (Consumer Confidence Report) or your water bill, or use our free interactive hardness map. Hardness can vary widely between neighboring utilities in Iowa.
Do I need a salt-based water softener at 20.5 gpg?
Not necessarily. Salt softeners add sodium to your water and need constant refills. LIMPEO treats limescale with an electromagnetic field — no salt, no chemicals, no maintenance — and keeps healthy minerals in your drinking water.