How hard is the water in Linn County, OR?
6.6 grains per gallon
Optional: a softener helps, but plenty of homes skip it.
The median hardness measured in Linn County, OR is 114 mg/L as calcium carbonate, which is 6.6 gpg. That is moderately hard on the USGS scale. It comes from 180 samples at 90 sites between 1990 and 2024, 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 4.3 and 9.3 gpg. That spread crosses a decision line, so some homes here land on a different answer. A $10 test strip on your own tap settles it. Confidence in the county figure: high (how it is measured).
What to do next
At 6.6 gpg this is your call. Look for white film on glasses and crust on the shower head: if you see little of either, you can live without one. If you do want one, a 24,000-grain unit is enough, so ask for that size rather than a bigger one. Because Linn County straddles a decision line, check your own tap with a $10 test strip before you spend anything.
More on when a softener is not worth it.
From 0.0 to 126.8 gpg
The softest single sample on record in Linn County was 0.8 mg/L and the hardest 2,170 mg/L, a 2,713-fold gap. The top quarter of sites read above 9.3 gpg and the bottom quarter below 4.3 gpg.
Wells 6.6 gpg, rivers and lakes 2.1 gpg
180 groundwater samples from 90 wells put the median at 113.5 mg/L. 669 surface samples from 38 sites put it at 35.3 mg/L. In Linn County the wells come out 4.5 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 145 lb of salt a year (4 bags of 40 lb, about $26), 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 $126 a year.
Sizing at 6.6 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 396 | 24,000 | 48 lb |
| 2 | 792 | 24,000 | 96 lb |
| 4 | 1,584 | 24,000 | 193 lb |
| 6 | 2,376 | 24,000 | 289 lb |
Linn County against the rest of Oregon
Among the 36 Oregon counties with data, Linn County is number 15 of 36 counting from the hardest. Across the whole country it is harder than 37% of counties.
Softest in Oregon: Columbia County at 1.4 gpg. Hardest: Malheur County at 17.8 gpg. Closest to Linn County: Josephine County (7), Marion County (7), Benton County (7.4).