How hard is the water in Hamilton County, IA?
22.6 grains per gallon
A softener will pay its way here.
The median hardness measured in Hamilton County, IA is 387 mg/L as calcium carbonate, which is 22.6 gpg. That is very hard on the USGS scale. It comes from 254 samples at 53 sites between 1990 and 2018, 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 19.9 and 26.8 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: high (how it is measured).
What to do next
At 22.6 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 11.3 to 38.6 gpg
The softest single sample on record in Hamilton County was 194 mg/L and the hardest 660 mg/L, a 3-fold gap. The top quarter of sites read above 26.8 gpg and the bottom quarter below 19.9 gpg.
Wells 22.6 gpg, rivers and lakes 21.6 gpg
254 groundwater samples from 53 wells put the median at 387 mg/L. 129 surface samples from 6 sites put it at 369.5 mg/L. In Hamilton County the wells come out 1.0 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 32,000-grain unit covers a week between regenerations. Expect about 494 lb of salt a year (13 bags of 40 lb, about $89), 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 $189 a year.
Sizing at 22.6 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 1,356 | 24,000 | 165 lb |
| 2 | 2,712 | 24,000 | 330 lb |
| 4 | 5,424 | 40,000 | 660 lb |
| 6 | 8,136 | 64,000 | 990 lb |
Hamilton County against the rest of Iowa
Among the 93 Iowa counties with data, Hamilton County is number 28 of 93 counting from the hardest. Across the whole country it is harder than 89% of counties.
Softest in Iowa: Taylor County at 8.2 gpg. Hardest: Pocahontas County at 45.3 gpg. Closest to Hamilton County: Wapello County (22.5), Wright County (22.5), Carroll County (22.8).