How hard is the water in Lafourche Parish, LA?
9 grains per gallon
A softener is worth it here.
The median hardness measured in Lafourche Parish, LA is 154 mg/L as calcium carbonate, which is 9 gpg. That is hard on the USGS scale. It comes from 1,164 samples at 25 sites between 1996 and 2024, drawn from every sampling site in the county, wells and surface water together.
How much it varies here
Half the sites came in between 7.1 and 186.9 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 9 gpg a softener is worth getting, mainly to protect the water heater and cut soap use. Get at least two quotes, ask each installer what grain capacity they are fitting, and check it against the sizing table below. Because Lafourche Parish straddles a decision line, check your own tap with a $10 test strip before you spend anything.
More on sizing a softener for your household.
From 3.1 to 234.5 gpg
The softest single sample on record in Lafourche Parish was 53 mg/L and the hardest 4,015 mg/L, a 76-fold gap. The top quarter of sites read above 186.9 gpg and the bottom quarter below 7.1 gpg. So even here some sites draw water soft enough to need nothing at all.
What a softener would cost to run
For a household of 3, a 24,000-grain unit covers a week between regenerations. Expect about 196 lb of salt a year (5 bags of 40 lb, about $35), 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 $135 a year.
Sizing at 9 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 540 | 24,000 | 66 lb |
| 2 | 1,080 | 24,000 | 131 lb |
| 4 | 2,160 | 24,000 | 263 lb |
| 6 | 3,240 | 24,000 | 394 lb |
Lafourche Parish against the rest of Louisiana
Among the 64 Louisiana counties with data, Lafourche Parish is number 27 of 64 counting from the hardest. Across the whole country it is harder than 47% of counties.
Softest in Louisiana: Lincoln Parish at 0.1 gpg. Hardest: St. Bernard Parish at 53.9 gpg. Closest to Lafourche Parish: Jefferson Davis Parish (9.3), St. James Parish (8.6), Evangeline Parish (9.4).