Cookeville, TN water hardness

Tap water hardness
56mg/L
3.3gpg
Soft

Reported by Cookeville Water Dept · October 2025

TN typical
89 mg/L
EPA health violations since 2016
1
Data
Utility report

The water in Cookeville carries roughly 56 mg/L of dissolved calcium and magnesium, or 3.3 grains per gallon. That is soft water. The number comes from Cookeville Water Dept, dated October 2025.

Cookeville on the hardness scale, with nearby cities
060120180240300360+TN typical 89Nolensville: 62 mg/LNolensville 62Lebanon: 78 mg/LLebanon 78Tullahoma: 81 mg/LTullahoma 81Gallatin: 82 mg/LGallatin 82Mount Juliet: 89 mg/LMount Juliet 89Green Hill: 89 mg/LGreen Hill 89Hendersonville: 89 mg/LHendersonville 89Murfreesboro: 101 mg/LMurfreesboro 101Smyrna: 200 mg/LSmyrna 200La Vergne: 200 mg/LLa Vergne 200Cookeville 56mg/L as calcium carbonate060120180240300360+TN 89Lebanon: 78 mg/LLebanon 78Gallatin: 82 mg/LGallatin 82Mount Juliet: 89 mg/LMount Juli. 89Murfreesboro: 101 mg/LMurfreesbo. 101Smyrna: 200 mg/LSmyrna 200La Vergne: 200 mg/LLa Vergne 20056 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

Cookeville sits 33 mg/L below the typical Tennessee figure of 89. None of the 10 nearest cities we track has softer water. The range nearby runs from 62 mg/L in Nolensville to 200 in Smyrna.

What 56 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 56 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 Cookeville's water system

Cookeville Water Dept · PWSID TN0000133

1 health-based violation since 2016

Serves about 49,711 people from surface water.

Health-based
1
Monitoring or reporting
1
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 byproduct12017Resolved

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 Cookeville water hard?

No. It measures about 56 mg/L (3.3 grains per gallon), which the USGS classes as soft.

What is the water hardness in Cookeville in grains per gallon?

About 3.3 gpg. One grain per gallon equals 17.1 mg/L, so 56 mg/L divided by 17.1 gives 3.3.

Has the Cookeville water system had EPA violations?

EPA records show 1 health-based violation for Cookeville Water Dept since 2016, involving Total trihalomethanes (TTHM). There were also 1 monitoring or reporting violation, which are about late or missing tests and notices.

Nearby cities

All 44 cities in Tennessee

Hardness data: TapWaterData US Water Hardness (utility report, October 22, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.