How hard is the water in Benton County, IA?
18.6 grains per gallon
A softener will pay its way here.
The median hardness measured in Benton County, IA is 319 mg/L as calcium carbonate, which is 18.6 gpg. That is very hard on the USGS scale. It comes from 42 samples at 20 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 15.4 and 26.3 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 18.6 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 13.1 to 49.1 gpg
The softest single sample on record in Benton County was 225 mg/L and the hardest 840 mg/L, a 4-fold gap. The top quarter of sites read above 26.3 gpg and the bottom quarter below 15.4 gpg.
Wells 18.6 gpg, rivers and lakes 15 gpg
42 groundwater samples from 20 wells put the median at 318.8 mg/L. 15 surface samples from 3 sites put it at 257 mg/L. In Benton County the wells come out 3.6 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 407 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 18.6 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 1,116 | 24,000 | 136 lb |
| 2 | 2,232 | 24,000 | 272 lb |
| 4 | 4,464 | 32,000 | 543 lb |
| 6 | 6,696 | 48,000 | 815 lb |
Benton County against the rest of Iowa
Among the 93 Iowa counties with data, Benton County is number 59 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 Benton County: Dubuque County (18.7), Jackson County (18.7), Washington County (18.7).