How hard is the water in Signal Mountain, TN?

Tap water hardness
69mg/L
4.0gpg
Moderately hard

Reported by Signal Mountain Water System · October 2025

TN typical
89 mg/L
EPA health violations since 2016
0
Softener for 3 people
24k grain
Data
Utility report

The water in Signal Mountain carries roughly 69 mg/L of dissolved calcium and magnesium, or 4.0 grains per gallon. That is moderately hard water. The number comes from Signal Mountain Water System, dated October 2025.

Signal Mountain on the hardness scale, with nearby cities
060120180240300360+TN typical 89Cookeville: 56 mg/LCookeville 56Red Bank: 70 mg/LRed Bank 70Chattanooga: 70 mg/LChattanooga 70East Ridge: 70 mg/LEast Ridge 70Harrison: 71 mg/LHarrison 71Tullahoma: 81 mg/LTullahoma 81Murfreesboro: 101 mg/LMurfreesboro 101Shelbyville: 130 mg/LShelbyville 130Oak Ridge: 132 mg/LOak Ridge 132Cleveland: 150 mg/LCleveland 150Signal Mountain 69mg/L as calcium carbonate060120180240300360+TN 89Red Bank: 70 mg/LRed Bank 70Chattanooga: 70 mg/LChattanooga 70East Ridge: 70 mg/LEast Ridge 70Harrison: 71 mg/LHarrison 71Tullahoma: 81 mg/LTullahoma 81Cleveland: 150 mg/LCleveland 15069 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

At 69 mg/L, Signal Mountain is 20 mg/L below the typical Tennessee figure of 89. Of the 10 nearest cities we track, 1 has softer water and 9 have harder. The range nearby runs from 56 mg/L in Cookeville to 150 in Cleveland.

What 69 mg/L means at home

You may see faint white spots on glasses and shower doors after the water dries.

Scale builds up slowly. A kettle or coffee maker needs descaling now and then, maybe every few months.

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

Optional. Plenty of households at this level live with it and descale the kettle now and then.

Water softener

Worth a look if spots on glass bother you, or if your tankless water heater manual asks for softer water.

Carbon filter

Improves taste and removes chlorine. It leaves calcium and magnesium in place.

Softener size for Signal Mountain

3 people × 75 gallons a day × 4.0 gpg = 904 grains a day. A 24,000-grain unit regenerates about every 26 days.

Size it for your household

EPA record for Signal Mountain's water system

Signal Mountain Water System · PWSID TN0000634

No health-based violations since 2016

Serves about 7,761 people from surface water.

Health-based
0
Monitoring or reporting
0
Open now
0

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 Signal Mountain water hard?

Somewhat. It measures about 69 mg/L (4.0 grains per gallon), which the USGS classes as moderately hard.

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

About 4.0 gpg. One grain per gallon equals 17.1 mg/L, so 69 mg/L divided by 17.1 gives 4.0.

What size water softener do I need in Signal Mountain?

For 3 people using 75 gallons each per day, 4.0 gpg works out to about 904 grains a day. A 24,000-grain softener covers that with a regeneration about every 26 days.

Has the Signal Mountain water system had EPA violations?

EPA records show no health-based violations for Signal Mountain Water System since 2016.

Nearby cities

All 44 cities in Tennessee

Hardness data: TapWaterData US Water Hardness (utility report, October 2, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.