Hard water in Dayton, OH
Reported by Montgomery County Water Services 1 PWS · September 2025
- OH typical
- 113 mg/L
- EPA health violations since 2016
- 0
- Softener for 3 people
- 24k grain
- Data
- Utility report
Tap water in Dayton has about 147 mg/L of hardness, which is 8.6 grains per gallon. On the USGS scale that counts as hard. The number comes from Montgomery County Water Services 1 PWS, dated September 2025.
At 147 mg/L, Dayton is 34 mg/L above the typical Ohio figure of 113. None of the 10 nearest cities we track has softer water. The range nearby runs from 147 mg/L in Moraine to 155 in Shiloh.
What 147 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 147 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.
3 people × 75 gallons a day × 8.6 gpg = 1,935 grains a day. A 24,000-grain unit regenerates about every 12 days.
EPA record for Dayton's water system
No health-based violations since 2016
Serves about 141,407 people from surface water.
- Health-based
- 0
- Monitoring or reporting
- 0
- Open now
- 0
EPA lists Dayton Public Water System as the system serving Dayton. The hardness figure above comes from a different system's report, which TapWaterData uses for Dayton.
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 Dayton water hard?
Yes. It measures about 147 mg/L (8.6 grains per gallon), which the USGS classes as hard.
What is the water hardness in Dayton in grains per gallon?
About 8.6 gpg. One grain per gallon equals 17.1 mg/L, so 147 mg/L divided by 17.1 gives 8.6.
What size water softener do I need in Dayton?
For 3 people using 75 gallons each per day, 8.6 gpg works out to about 1,935 grains a day. A 24,000-grain softener covers that with a regeneration about every 12 days.
Has the Dayton water system had EPA violations?
EPA records show no health-based violations for Dayton Public Water System since 2016.
Nearby cities
- Shiloh155 mg/LHard
- Riverside149 mg/LHard
- Oakwood148 mg/LHard
- Moraine147 mg/LHard
- Trotwood147 mg/LHard
- Vandalia155 mg/LHard
- Kettering147 mg/LHard
- Huber Heights155 mg/LHard
- Englewood155 mg/LHard
- Beavercreek149 mg/LHard
Hardness data: TapWaterData US Water Hardness (utility report, September 16, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.