How hard is the water in Des Moines County, IA?
15.1 grains per gallon
A softener will pay its way here.
The median hardness measured in Des Moines County, IA is 259 mg/L as calcium carbonate, which is 15.1 gpg. That is very hard on the USGS scale. It comes from 16 samples at 11 sites between 1990 and 2017, drawn from groundwater wells, which is what most taps and private wells in the county draw on.
How much it varies here
Half the sites came in between 13.3 and 18.6 gpg. The whole middle of that range gives the same answer, so a test of your own tap is unlikely to change it. Confidence in the county figure: medium (how it is measured).
What to do next
At 15.1 gpg a softener pays its way here. Before you buy, check the quoted unit's grain capacity against the sizing table below, and ask whether it regenerates on demand, which uses less salt than a timer. Call your utility for its own report if you are on city water.
More on sizing a softener for your household.
From 6.2 to 20.1 gpg
The softest single sample on record in Des Moines County was 106 mg/L and the hardest 344 mg/L, a 3-fold gap. The top quarter of sites read above 18.6 gpg and the bottom quarter below 13.3 gpg.
Wells 15.1 gpg, rivers and lakes 14 gpg
16 groundwater samples from 11 wells put the median at 259 mg/L. 69 surface samples from 3 sites put it at 240 mg/L. In Des Moines County the wells come out 1.1 gpg harder. Groundwater sits in contact with rock for years and picks up calcium and magnesium as it goes, so wells usually read harder. The two sources are close, so the county figure should hold whichever one your tap is on.
What a softener would cost to run
For a household of 3, a 24,000-grain unit covers a week between regenerations. Expect about 330 lb of salt a year (9 bags of 40 lb, about $59), and roughly 2,346 gallons of regeneration water. Installed, most units run $1,000 to $4,500; spread over 15 years with salt, that is about $159 a year.
Sizing at 15.1 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 906 | 24,000 | 110 lb |
| 2 | 1,812 | 24,000 | 220 lb |
| 4 | 3,624 | 32,000 | 441 lb |
| 6 | 5,436 | 40,000 | 661 lb |
Des Moines County against the rest of Iowa
Among the 93 Iowa counties with data, Des Moines County is number 78 of 93 counting from the hardest. Across the whole country it is harder than 70% of counties.
Softest in Iowa: Taylor County at 8.2 gpg. Hardest: Pocahontas County at 45.3 gpg. Closest to Des Moines County: Van Buren County (15.5), Madison County (14.6), Warren County (14.6).