How hard is the water in Troy, MI?

Tap water hardness
100mg/L
5.8gpg
Moderately hard

Reported by Troy · October 2025

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

Tap water in Troy has about 100 mg/L of hardness, which is 5.8 grains per gallon. On the USGS scale that counts as moderately hard. The number comes from Troy, dated October 2025.

Troy on the hardness scale, with nearby cities
060120180240300360+MI typical 112Berkley: 85 mg/LBerkley 85Beverly Hills: 90 mg/LBeverly Hills 90Auburn Hills: 90 mg/LAuburn Hills 90Royal Oak: 96 mg/LRoyal Oak 96Rochester Hills: 100 mg/LRochester Hills 100Sterling Heights: 103 mg/LSterling Heights 103Utica: 103 mg/LUtica 103Rochester: 104 mg/LRochester 104Madison Heights: 277 mg/LMadison Heights 277Oak Park: 277 mg/LOak Park 277Troy 100mg/L as calcium carbonate060120180240300360+MI 112Berkley: 85 mg/LBerkley 85Beverly Hills: 90 mg/LBeverly Hi. 90Royal Oak: 96 mg/LRoyal Oak 96Rochester Hills: 100 mg/LRochester. 100Sterling Heights: 103 mg/LSterling H. 103Madison Heights: 277 mg/LMadison He. 277100 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 100 mg/L, Troy is 12 mg/L below the typical Michigan figure of 112. Of the 10 nearest cities we track, 4 have softer water and 5 have harder. The range nearby runs from 85 mg/L in Berkley to 277 in Madison Heights.

What 100 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 Troy

3 people × 75 gallons a day × 5.8 gpg = 1,310 grains a day. A 24,000-grain unit regenerates about every 18 days.

Size it for your household

EPA record for Troy's water system

Troy · PWSID MI0006690

No health-based violations since 2016

Serves about 85,854 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 Troy water hard?

Somewhat. It measures about 100 mg/L (5.8 grains per gallon), which the USGS classes as moderately hard.

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

About 5.8 gpg. One grain per gallon equals 17.1 mg/L, so 100 mg/L divided by 17.1 gives 5.8.

What size water softener do I need in Troy?

For 3 people using 75 gallons each per day, 5.8 gpg works out to about 1,310 grains a day. A 24,000-grain softener covers that with a regeneration about every 18 days.

Has the Troy water system had EPA violations?

EPA records show no health-based violations for Troy since 2016.

Nearby cities

All 118 cities in Michigan

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.