How hard is the water in Delaware, OH?
Reported by Del-CO Water Company, Inc. · June 2025
- OH typical
- 113 mg/L
- EPA health violations since 2016
- 0
- Softener for 3 people
- 24k grain
- Data
- Utility report
The water in Delaware carries roughly 94 mg/L of dissolved calcium and magnesium, or 5.5 grains per gallon. That is moderately hard water. The number comes from Del-CO Water Company, Inc., dated June 2025.
At 94 mg/L, Delaware is 19 mg/L below the typical Ohio figure of 113. None of the 10 nearest cities we track has softer water. The range nearby runs from 94 mg/L in Powell to 316 in Marysville.
What 94 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.
3 people × 75 gallons a day × 5.5 gpg = 1,235 grains a day. A 24,000-grain unit regenerates about every 19 days.
EPA record for Delaware's water system
No health-based violations since 2016
Serves about 150,000 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 Delaware water hard?
Somewhat. It measures about 94 mg/L (5.5 grains per gallon), which the USGS classes as moderately hard.
What is the water hardness in Delaware in grains per gallon?
About 5.5 gpg. One grain per gallon equals 17.1 mg/L, so 94 mg/L divided by 17.1 gives 5.5.
What size water softener do I need in Delaware?
For 3 people using 75 gallons each per day, 5.5 gpg works out to about 1,235 grains a day. A 24,000-grain softener covers that with a regeneration about every 19 days.
Has the Delaware water system had EPA violations?
EPA records show no health-based violations for Del-CO Water Company, Inc. since 2016.
Nearby cities
- Powell94 mg/LModerately hard
- Dublin97 mg/LModerately hard
- Worthington97 mg/LModerately hard
- Westerville124 mg/LHard
- Marysville316 mg/LVery hard
- Upper Arlington97 mg/LModerately hard
- Hilliard97 mg/LModerately hard
- Gahanna96 mg/LModerately hard
- New Albany97 mg/LModerately hard
- Grandview Heights97 mg/LModerately hard
Hardness data: TapWaterData US Water Hardness (utility report, June 30, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.