Stone Mountain, GA water hardness

Tap water hardness
18mg/L
1.0gpg
Soft

Reported by Dekalb County · September 2025

GA typical
28 mg/L
EPA health violations since 2016
0
Data
Utility report

The water in Stone Mountain carries roughly 18 mg/L of dissolved calcium and magnesium, or 1.0 grains per gallon. That is soft water. The number comes from Dekalb County, dated September 2025.

Stone Mountain on the hardness scale, with nearby cities
060120180240300360+GA typical 28Tucker: 18 mg/LTucker 18Clarkston: 18 mg/LClarkston 18Redan: 18 mg/LRedan 18Scottdale: 18 mg/LScottdale 18Belvedere Park: 18 mg/LBelvedere Park 18North Decatur: 18 mg/LNorth Decatur 18Candler-McAfee: 18 mg/LCandler-McAfee 18Stonecrest: 18 mg/LStonecrest 18Panthersville: 18 mg/LPanthersville 18Decatur: 24 mg/LDecatur 24Stone Mountain 18mg/L as calcium carbonate060120180240300360+GA 28Tucker: 18 mg/LTucker 18Clarkston: 18 mg/LClarkston 18Redan: 18 mg/LRedan 18Scottdale: 18 mg/LScottdale 18Belvedere Park: 18 mg/LBelvedere. 18North Decatur: 18 mg/LNorth Deca. 1818 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

Stone Mountain sits close to the typical Georgia figure of 28 mg/L. None of the 10 nearest cities we track has softer water. The range nearby runs from 18 mg/L in Tucker to 24 in Decatur.

What 18 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 18 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 Stone Mountain's water system

Dekalb County · PWSID GA0890001

No health-based violations since 2016

Serves about 743,000 people from surface water.

Health-based
0
Monitoring or reporting
1
Open now
0

TapWaterData ties Stone Mountain to this system. EPA's service-area records do not name Stone Mountain, so check the utility printed on your water bill.

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 Stone Mountain water hard?

No. It measures about 18 mg/L (1.0 grains per gallon), which the USGS classes as soft.

What is the water hardness in Stone Mountain in grains per gallon?

About 1.0 gpg. One grain per gallon equals 17.1 mg/L, so 18 mg/L divided by 17.1 gives 1.0.

Has the Stone Mountain water system had EPA violations?

EPA records show no health-based violations for Dekalb County since 2016. There were also 1 monitoring or reporting violation, which are about late or missing tests and notices.

Nearby cities

All 85 cities in Georgia

Hardness data: TapWaterData US Water Hardness (utility report, September 29, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.