Bay St. Louis, MS water hardness

Tap water hardness
4mg/L
0.3gpg
Soft

Reported by City of Bay ST Louis · February 2025

MS typical
38 mg/L
EPA health violations since 2016
5
Data
Utility report

Tap water in Bay St. Louis has about 4 mg/L of hardness, which is 0.3 grains per gallon. On the USGS scale that counts as soft. The number comes from City of Bay ST Louis, dated February 2025.

Bay St. Louis on the hardness scale, with nearby cities
060120180240300360+MS typical 38Meridian: 15 mg/LMeridian 15Byram: 38 mg/LByram 38Jackson: 38 mg/LJackson 38Clinton: 38 mg/LClinton 38Columbus: 51 mg/LColumbus 51Oxford: 77 mg/LOxford 77Bay St. Louis 4mg/L as calcium carbonate060120180240300360+MS 38Meridian: 15 mg/LMeridian 15Byram: 38 mg/LByram 38Jackson: 38 mg/LJackson 38Clinton: 38 mg/LClinton 38Columbus: 51 mg/LColumbus 51Oxford: 77 mg/LOxford 774 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

Bay St. Louis sits 34 mg/L below the typical Mississippi figure of 38. None of the 6 nearest cities we track has softer water. The range nearby runs from 15 mg/L in Meridian to 77 in Oxford.

What 4 mg/L means at home

Soap and shampoo lather with very little product. Kettles and showerheads stay mostly free of white crust.

Some people notice that soap feels slow to rinse off in soft water. That slippery feel is normal and harmless.

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

Nothing, as far as hardness goes. At 4 mg/L a softener would have almost nothing to remove.

Carbon filter

If the water tastes of chlorine, a pitcher or faucet carbon filter takes care of that. It does not change hardness.

EPA record for Bay St. Louis's water system

City of Bay ST Louis · PWSID MS0230001

5 health-based violations since 2016

Serves about 9,284 people from groundwater.

Health-based
5
Monitoring or reporting
6
Open now
0
20162017201820192020202120222023202420252026Total trihalomethanes (TTHM)'16'18'20'22'24'26Total trihalomethanes (TTHM)
Each dot is one health-based violation, placed at the start of its compliance period.
Contaminant or ruleViolationsPeriodStatus
Total trihalomethanes (TTHM)a disinfection byproduct52022–2024Resolved

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 Bay St. Louis water hard?

No. It measures about 4 mg/L (0.3 grains per gallon), which the USGS classes as soft.

What is the water hardness in Bay St. Louis in grains per gallon?

About 0.3 gpg. One grain per gallon equals 17.1 mg/L, so 4 mg/L divided by 17.1 gives 0.3.

Has the Bay St. Louis water system had EPA violations?

EPA records show 5 health-based violations for City of Bay ST Louis since 2016, involving Total trihalomethanes (TTHM). There were also 6 monitoring or reporting violations, which are about late or missing tests and notices.

Nearby cities

All 7 cities in Mississippi

Hardness data: TapWaterData US Water Hardness (utility report, February 12, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.