How hard is the water in Ouachita Parish, LA?

1.6 grains per gallon

You do not need a softener here.

The median hardness measured in Ouachita Parish, LA is 27 mg/L as calcium carbonate, which is 1.6 gpg. That is soft on the USGS scale. It comes from 76 samples at 16 sites between 1993 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 8 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 1.6 gpg the most a softener would fix is the odd water spot. If a salesperson in Ouachita Parish says otherwise, ask to see their reading in grains per gallon and compare it with this one. Because Ouachita Parish 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 0.1 to 35.9 gpg

The softest single sample on record in Ouachita Parish was 1.6 mg/L and the hardest 614 mg/L, a 384-fold gap. The top quarter of sites read above 8 gpg and the bottom quarter below 0.2 gpg. So even in a soft county, a handful of wells here produce water hard enough to scale a heater.

Wells 1.6 gpg, rivers and lakes 1.7 gpg

76 groundwater samples from 16 wells put the median at 26.9 mg/L. 418 surface samples from 7 sites put it at 28.5 mg/L. In Ouachita Parish the rivers and lakes come out 0.1 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.

Ouachita Parish against the rest of Louisiana

Among the 64 Louisiana counties with data, Ouachita Parish is number 44 of 64 counting from the hardest. Across the whole country it is harder than 13% of counties.

Softest in Louisiana: Lincoln Parish at 0.1 gpg. Hardest: St. Bernard Parish at 53.9 gpg. Closest to Ouachita Parish: LaSalle Parish (1.5), Webster Parish (1.6), De Soto Parish (1.1).