Hard water in Gretna, LA
Reported by New Orleans Carrollton WW · September 2025
- LA typical
- 102 mg/L
- EPA health violations since 2016
- 1
- Softener for 3 people
- 24k grain
- Data
- Utility report
Gretna water measures 153 mg/L (8.9 gpg) of hardness, hard by USGS standards. The number comes from New Orleans Carrollton WW, dated September 2025.
Gretna sits 51 mg/L above the typical Louisiana figure of 102. Of the 10 nearest cities we track, 3 have softer water and 5 have harder. The range nearby runs from 42 mg/L in Slidell to 154 in Marrero.
What 153 mg/L means at home
Expect white crust on faucets and showerheads, plus spots on dishes that come out of the dishwasher.
Kettles collect scale quickly. Water heaters build up sediment at the bottom of the tank, which makes them work harder over time.
Soap and detergent need a little more to lather, and soap scum shows up in the tub.
Hardness is not a health problem, and EPA sets no limit for it. It is a matter of scale and soap.
What to do about it
At 153 mg/L most of the trouble is scale, and only a few things deal with it.
Ion-exchange water softener
The standard whole-house fix. It swaps calcium and magnesium for sodium or potassium and needs salt plus a drain. Size it with the calculator below.
Salt-free conditioner
No salt and no drain line. It changes how minerals form scale instead of removing them, so water still tests hard.
Reverse osmosis or carbon filter
Under-sink reverse osmosis removes minerals from drinking water only. Plain carbon filters improve taste but do not soften.
3 people × 75 gallons a day × 8.9 gpg = 2,014 grains a day. A 24,000-grain unit regenerates about every 11 days.
EPA record for Gretna's water system
1 health-based violation since 2016
Serves about 334,903 people from surface water.
- Health-based
- 1
- Monitoring or reporting
- 4
- Open now
- 0
TapWaterData ties Gretna to this system. EPA's service-area records do not name Gretna, so check the utility printed on your water bill.
| Contaminant or rule | Violations | Period | Status |
|---|---|---|---|
| Surface Water Treatment Rulefiltration and disinfection | 1 | 2025 | Resolved |
Health-based means a contaminant above its legal limit or a missed treatment step. Monitoring and reporting violations are late or missing tests and notices. Source: EPA ECHO, 2026Q3 export, violations with periods starting 2016 or later. Full EPA record.
Questions
Is Gretna water hard?
Yes. It measures about 153 mg/L (8.9 grains per gallon), which the USGS classes as hard.
What is the water hardness in Gretna in grains per gallon?
About 8.9 gpg. One grain per gallon equals 17.1 mg/L, so 153 mg/L divided by 17.1 gives 8.9.
What size water softener do I need in Gretna?
For 3 people using 75 gallons each per day, 8.9 gpg works out to about 2,014 grains a day. A 24,000-grain softener covers that with a regeneration about every 11 days.
Has the Gretna water system had EPA violations?
EPA records show 1 health-based violation for New Orleans Carrollton Water Works since 2016, involving Surface Water Treatment Rule. There were also 4 monitoring or reporting violations, which are about late or missing tests and notices.
Nearby cities
- Marrero154 mg/LHard
- Belle Chasse153 mg/LHard
- Westwego154 mg/LHard
- Bridge City154 mg/LHard
- Jefferson154 mg/LHard
- Elmwood154 mg/LHard
- Metairie135 mg/LHard
- New Orleans153 mg/LHard
- Slidell42 mg/LSoft
- Mandeville48 mg/LSoft
Hardness data: TapWaterData US Water Hardness (utility report, September 19, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.