Hard water in Flint, MI

Tap water hardness
137mg/L
8.0gpg
HardReports range 95–137

Reported by Flint, City of · February 2025

MI typical
112 mg/L
EPA health violations since 2016
1
Softener for 3 people
24k grain
Data
Utility report

Flint water measures 137 mg/L (8.0 gpg) of hardness, hard by USGS standards. The number comes from Flint, City of, dated February 2025. Reports for this system disagree, with values from 95 to 137 mg/L.

Flint on the hardness scale, with nearby cities
060120180240300360+MI typical 112Swartz Creek: 98 mg/LSwartz Creek 98Flushing: 113 mg/LFlushing 113Beecher: 144 mg/LBeecher 144Burton: 150 mg/LBurton 150Grand Blanc: 157 mg/LGrand Blanc 157Davison: 181 mg/LDavison 181Fenton: 315 mg/LFenton 315Holly: 323 mg/LHolly 323Owosso: 339 mg/LOwosso 339Lapeer: 354 mg/LLapeer 354Flint 137mg/L as calcium carbonate060120180240300360+MI 112Swartz Creek: 98 mg/LSwartz Cre. 98Flushing: 113 mg/LFlushing 113Beecher: 144 mg/LBeecher 144Burton: 150 mg/LBurton 150Grand Blanc: 157 mg/LGrand Blanc 157Davison: 181 mg/LDavison 181137 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

Flint sits 25 mg/L above the typical Michigan figure of 112. Of the 10 nearest cities we track, 2 have softer water and 8 have harder. The range nearby runs from 98 mg/L in Swartz Creek to 354 in Lapeer.

What 137 mg/L means at home

Expect white crust on faucets and showerheads, plus spots on dishes that come out of the dishwasher.

Kettles collect scale quickly. Water heaters build up sediment at the bottom of the tank, which makes them work harder over time.

Soap and detergent need a little more to lather, and soap scum shows up in the tub.

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

At 137 mg/L most of the trouble is scale, and only a few things deal with it.

Ion-exchange water softener

The standard whole-house fix. It swaps calcium and magnesium for sodium or potassium and needs salt plus a drain. Size it with the calculator below.

Salt-free conditioner

No salt and no drain line. It changes how minerals form scale instead of removing them, so water still tests hard.

Reverse osmosis or carbon filter

Under-sink reverse osmosis removes minerals from drinking water only. Plain carbon filters improve taste but do not soften.

Softener size for Flint

3 people × 75 gallons a day × 8.0 gpg = 1,807 grains a day. A 24,000-grain unit regenerates about every 13 days.

Size it for your household

EPA record for Flint's water system

Flint, City of · PWSID MI0002310

1 health-based violation since 2016

Serves about 81,252 people from surface water.

Health-based
1
Monitoring or reporting
3
Open now
0
20162017201820192020202120222023202420252026Lead and Copper Rule'16'18'20'22'24'26Lead and Copper Rule
Each dot is one health-based violation, placed at the start of its compliance period.
Contaminant or ruleViolationsPeriodStatus
Lead and Copper Rulecorrosion control and lead sampling12024Resolved

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 Flint water hard?

Yes. It measures about 137 mg/L (8.0 grains per gallon), which the USGS classes as hard.

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

About 8.0 gpg. One grain per gallon equals 17.1 mg/L, so 137 mg/L divided by 17.1 gives 8.0.

What size water softener do I need in Flint?

For 3 people using 75 gallons each per day, 8.0 gpg works out to about 1,807 grains a day. A 24,000-grain softener covers that with a regeneration about every 13 days.

Has the Flint water system had EPA violations?

EPA records show 1 health-based violation for Flint, City of since 2016, involving Lead and Copper Rule. There were also 3 monitoring or reporting violations, which are about late or missing tests and notices.

Nearby cities

All 118 cities in Michigan

Hardness data: TapWaterData US Water Hardness (utility report, February 6, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.