Fort Smith, AR water hardness

Tap water hardness
35mg/L
2.1gpg
Soft

Calculated from the utility's calcium and magnesium results · March 2025

AR typical
39 mg/L
EPA health violations since 2016
1
Data
Calculated from utility data

The water in Fort Smith carries roughly 35 mg/L of dissolved calcium and magnesium, or 2.1 grains per gallon. That is soft water. TapWaterData worked it out from the calcium and magnesium levels the local utility reports (March 2025).

Fort Smith on the hardness scale, with nearby cities
060120180240300360+AR typical 39Mena: 8 mg/LMena 8Alma: 15 mg/LAlma 15Clarksville: 31 mg/LClarksville 31Van Buren: 35 mg/LVan Buren 35Greenwood: 52 mg/LGreenwood 52Prairie Grove: 68 mg/LPrairie Grove 68Farmington: 77 mg/LFarmington 77Fayetteville: 77 mg/LFayetteville 77Springdale: 77 mg/LSpringdale 77Siloam Springs: 113 mg/LSiloam Springs 113Fort Smith 35mg/L as calcium carbonate060120180240300360+AR 39Alma: 15 mg/LAlma 15Clarksville: 31 mg/LClarksville 31Van Buren: 35 mg/LVan Buren 35Greenwood: 52 mg/LGreenwood 52Prairie Grove: 68 mg/LPrairie Gr. 68Farmington: 77 mg/LFarmington 7735 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

Fort Smith sits close to the typical Arkansas figure of 39 mg/L. Of the 10 nearest cities we track, 3 have softer water and 6 have harder. The range nearby runs from 8 mg/L in Mena to 113 in Siloam Springs.

What 35 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 35 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 Fort Smith's water system

Fort Smith Water Utilities · PWSID AR0000507

1 health-based violation since 2016

Serves about 86,209 people from surface water.

Health-based
1
Monitoring or reporting
0
Open now
0

EPA lists this system as serving Fort Smith.

20162017201820192020202120222023202420252026Surface Water Treatment Rule'16'18'20'22'24'26Surface Water Treatment Rule
Each dot is one health-based violation, placed at the start of its compliance period.
Contaminant or ruleViolationsPeriodStatus
Surface Water Treatment Rulefiltration and disinfection12017Resolved

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 Fort Smith water hard?

No. It measures about 35 mg/L (2.1 grains per gallon), which the USGS classes as soft.

What is the water hardness in Fort Smith in grains per gallon?

About 2.1 gpg. One grain per gallon equals 17.1 mg/L, so 35 mg/L divided by 17.1 gives 2.1.

Has the Fort Smith water system had EPA violations?

EPA records show 1 health-based violation for Fort Smith Water Utilities since 2016, involving Surface Water Treatment Rule.

Nearby cities

All 46 cities in Arkansas

Hardness data: TapWaterData US Water Hardness (calculated from utility data, March 6, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.