How hard is the water in Washington Parish, LA?

0.2 grains per gallon

You do not need a softener here.

The median hardness measured in Washington Parish, LA is 4 mg/L as calcium carbonate, which is 0.2 gpg. That is soft on the USGS scale. It comes from 14 samples at 8 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 0.2 and 0.4 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

You can skip the softener. At 0.2 gpg the most a softener would fix is the odd water spot. If a salesperson in Washington Parish says otherwise, ask to see their reading in grains per gallon and compare it with this one.

More on when a softener is not worth it.

From 0.1 to 1.1 gpg

The softest single sample on record in Washington Parish was 0.9 mg/L and the hardest 18.7 mg/L, a 21-fold gap. The top quarter of sites read above 0.4 gpg and the bottom quarter below 0.2 gpg.

Wells 0.2 gpg, rivers and lakes 0.8 gpg

14 groundwater samples from 8 wells put the median at 4.2 mg/L. 519 surface samples from 10 sites put it at 14 mg/L. In Washington Parish the rivers and lakes come out 0.6 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.

Washington Parish against the rest of Louisiana

Among the 64 Louisiana counties with data, Washington Parish is number 62 of 64 counting from the hardest. Across the whole country it is harder than 0% of counties.

Softest in Louisiana: Lincoln Parish at 0.1 gpg. Hardest: St. Bernard Parish at 53.9 gpg. Closest to Washington Parish: Sabine Parish (0.3), St. Tammany Parish (0.3), West Baton Rouge Parish (0.3).