How hard is the water in Washington County, IA?
18.7 grains per gallon
A softener will pay its way here.
The median hardness measured in Washington County, IA is 320 mg/L as calcium carbonate, which is 18.7 gpg. That is very hard on the USGS scale. It comes from 36 samples at 9 sites between 1992 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 17.5 and 23.8 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 18.7 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 8.9 to 47.3 gpg
The softest single sample on record in Washington County was 152 mg/L and the hardest 809 mg/L, a 5-fold gap. The top quarter of sites read above 23.8 gpg and the bottom quarter below 17.5 gpg.
Wells 18.7 gpg, rivers and lakes 11.3 gpg
36 groundwater samples from 9 wells put the median at 320 mg/L. 1 surface samples from 1 sites put it at 193 mg/L. In Washington County the wells come out 7.4 gpg harder. Groundwater sits in contact with rock for years and picks up calcium and magnesium as it goes, so wells usually read harder. A utility here that draws from the river can deliver noticeably different water from a private well next door.
What a softener would cost to run
For a household of 3, a 24,000-grain unit covers a week between regenerations. Expect about 408 lb of salt a year (11 bags of 40 lb, about $73), 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 $173 a year.
Sizing at 18.7 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 1,122 | 24,000 | 137 lb |
| 2 | 2,244 | 24,000 | 273 lb |
| 4 | 4,488 | 32,000 | 546 lb |
| 6 | 6,732 | 48,000 | 819 lb |
Washington County against the rest of Iowa
Among the 93 Iowa counties with data, Washington County is number 56 of 93 counting from the hardest. Across the whole country it is harder than 81% of counties.
Softest in Iowa: Taylor County at 8.2 gpg. Hardest: Pocahontas County at 45.3 gpg. Closest to Washington County: Dubuque County (18.7), Jackson County (18.7), Benton County (18.6).