How hard is the water in Brentwood, TN?

Tap water hardness
89mg/L
5.2gpg
Moderately hard

Reported by Metro Water Services · October 2025

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

Brentwood water measures 89 mg/L (5.2 gpg) of hardness, moderately hard by USGS standards. The number comes from Metro Water Services, dated October 2025.

Brentwood on the hardness scale, with nearby cities
060120180240300360+TN typical 89Nolensville: 62 mg/LNolensville 62Nashville: 89 mg/LNashville 89Green Hill: 89 mg/LGreen Hill 89Mount Juliet: 89 mg/LMount Juliet 89Ashland City: 89 mg/LAshland City 89Franklin: 98 mg/LFranklin 98Murfreesboro: 101 mg/LMurfreesboro 101Spring Hill: 138 mg/LSpring Hill 138La Vergne: 200 mg/LLa Vergne 200Smyrna: 200 mg/LSmyrna 200Brentwood 89mg/L as calcium carbonate060120180240300360+TN 89Nolensville: 62 mg/LNolensville 62Nashville: 89 mg/LNashville 89Franklin: 98 mg/LFranklin 98Spring Hill: 138 mg/LSpring Hill 138La Vergne: 200 mg/LLa Vergne 200Smyrna: 200 mg/LSmyrna 20089 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 89 mg/L, Brentwood is close to the typical Tennessee figure of 89 mg/L. Of the 10 nearest cities we track, 1 has softer water and 5 have harder. The range nearby runs from 62 mg/L in Nolensville to 200 in La Vergne.

What 89 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 Brentwood

3 people × 75 gallons a day × 5.2 gpg = 1,166 grains a day. A 24,000-grain unit regenerates about every 20 days.

Size it for your household

EPA record for Brentwood's water system

Brentwood Water Department · PWSID TN0000069

No health-based violations since 2016

Serves about 30,645 people from surface water.

Health-based
0
Monitoring or reporting
1
Open now
0

EPA lists Brentwood Water Department as the system serving Brentwood. The hardness figure above comes from a different system's report, which TapWaterData uses for Brentwood.

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 Brentwood water hard?

Somewhat. It measures about 89 mg/L (5.2 grains per gallon), which the USGS classes as moderately hard.

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

About 5.2 gpg. One grain per gallon equals 17.1 mg/L, so 89 mg/L divided by 17.1 gives 5.2.

What size water softener do I need in Brentwood?

For 3 people using 75 gallons each per day, 5.2 gpg works out to about 1,166 grains a day. A 24,000-grain softener covers that with a regeneration about every 20 days.

Has the Brentwood water system had EPA violations?

EPA records show no health-based violations for Brentwood Water Department since 2016. 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 7, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.