How hard is the water in Allen Parish, LA?

0.7 grains per gallon

You do not need a softener here.

The median hardness measured in Allen Parish, LA is 11 mg/L as calcium carbonate, which is 0.7 gpg. That is soft on the USGS scale. It comes from 27 samples at 19 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 0.4 and 2.5 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 0.7 gpg the most a softener would fix is the odd water spot. If a salesperson in Allen 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 7.2 gpg

The softest single sample on record in Allen Parish was 1.4 mg/L and the hardest 124 mg/L, an 89-fold gap. The top quarter of sites read above 2.5 gpg and the bottom quarter below 0.4 gpg.

Wells 0.7 gpg, rivers and lakes 2.1 gpg

27 groundwater samples from 19 wells put the median at 11.2 mg/L. 644 surface samples from 15 sites put it at 35.9 mg/L. In Allen Parish the rivers and lakes come out 1.4 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.

Allen Parish against the rest of Louisiana

Among the 64 Louisiana counties with data, Allen Parish is number 52 of 64 counting from the hardest. Across the whole country it is harder than 3% of counties.

Softest in Louisiana: Lincoln Parish at 0.1 gpg. Hardest: St. Bernard Parish at 53.9 gpg. Closest to Allen Parish: Vernon Parish (0.6), Jackson Parish (0.7), Tangipahoa Parish (0.5).