How hard is the water in Howard County, MD?
2.5 grains per gallon
You do not need a softener here.
The median hardness measured in Howard County, MD is 42 mg/L as calcium carbonate, which is 2.5 gpg. That is soft on the USGS scale. It comes from 63 samples at 53 sites between 1990 and 2019, 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 1.7 and 4.2 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
You can skip the softener. At 2.5 gpg the most a softener would fix is the odd water spot. If a salesperson in Howard County says otherwise, ask to see their reading in grains per gallon and compare it with this one. Because Howard 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 0.5 to 14.6 gpg
The softest single sample on record in Howard County was 8.6 mg/L and the hardest 250 mg/L, a 29-fold gap. The top quarter of sites read above 4.2 gpg and the bottom quarter below 1.7 gpg. So even in a soft county, a handful of wells here produce water hard enough to scale a heater.
Wells 2.5 gpg, rivers and lakes 4 gpg
63 groundwater samples from 53 wells put the median at 42.2 mg/L. 22 surface samples from 10 sites put it at 68 mg/L. In Howard County the rivers and lakes come out 1.5 gpg harder. Here the surface water reads harder than the wells, which often points to streams fed by limestone springs or irrigation return flow. The two sources are close, so the county figure should hold whichever one your tap is on.
Howard County against the rest of Maryland
Among the 24 Maryland counties with data, Howard County is number 19 of 24 counting from the hardest. Across the whole country it is harder than 19% of counties.
Softest in Maryland: Charles County at 0.3 gpg. Hardest: Washington County at 18.5 gpg. Closest to Howard County: Caroline County (2.3), Somerset County (2.7), Anne Arundel County (2.1).