Hard water in Pontiac, MI

Tap water hardness
121mg/L
7.1gpg
Hard

Reported by West Bloomfield Township · 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 Pontiac has about 121 mg/L of hardness, which is 7.1 grains per gallon. On the USGS scale that counts as hard. The number comes from West Bloomfield Township, dated October 2025.

Pontiac on the hardness scale, with nearby cities
060120180240300360+MI typical 112Berkley: 85 mg/LBerkley 85Auburn Hills: 90 mg/LAuburn Hills 90Beverly Hills: 90 mg/LBeverly Hills 90Royal Oak: 96 mg/LRoyal Oak 96Rochester Hills: 100 mg/LRochester Hills 100Troy: 100 mg/LTroy 100Utica: 103 mg/LUtica 103Rochester: 104 mg/LRochester 104Farmington Hills: 119 mg/LFarmington Hills 119Madison Heights: 277 mg/LMadison Heights 277Pontiac 121mg/L as calcium carbonate060120180240300360+MI 112Berkley: 85 mg/LBerkley 85Auburn Hills: 90 mg/LAuburn Hil. 90Beverly Hills: 90 mg/LBeverly Hi. 90Rochester Hills: 100 mg/LRochester. 100Troy: 100 mg/LTroy 100Rochester: 104 mg/LRochester 104121 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

Pontiac sits close to the typical Michigan figure of 112 mg/L. Of the 10 nearest cities we track, 9 have softer water and 1 has harder. The range nearby runs from 85 mg/L in Berkley to 277 in Madison Heights.

What 121 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 121 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 Pontiac

3 people × 75 gallons a day × 7.1 gpg = 1,588 grains a day. A 24,000-grain unit regenerates about every 15 days.

Size it for your household

EPA record for Pontiac's water system

Pontiac · PWSID MI0005440

No health-based violations since 2016

Serves about 63,776 people from surface water.

Health-based
0
Monitoring or reporting
0
Open now
0

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

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 Pontiac water hard?

Yes. It measures about 121 mg/L (7.1 grains per gallon), which the USGS classes as hard.

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

About 7.1 gpg. One grain per gallon equals 17.1 mg/L, so 121 mg/L divided by 17.1 gives 7.1.

What size water softener do I need in Pontiac?

For 3 people using 75 gallons each per day, 7.1 gpg works out to about 1,588 grains a day. A 24,000-grain softener covers that with a regeneration about every 15 days.

Has the Pontiac water system had EPA violations?

EPA records show no health-based violations for Pontiac 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.