How hard is the water in Hilliard, OH?

Tap water hardness

97mg/L

5.7gpg

Moderately hard

Reported by Columbus Public Water System · September 2025

OH typical: 113 mg/L
EPA health violations since 2016: 1
Softener for 3 people: 24k grain
Data: Utility report

The water in Hilliard carries roughly 97 mg/L of dissolved calcium and magnesium, or 5.7 grains per gallon. That is moderately hard water. The number comes from Columbus Public Water System, dated September 2025.

Hilliard on the hardness scale, with nearby cities

Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

At 97 mg/L, Hilliard is 16 mg/L below the typical Ohio figure of 113. Of the 10 nearest cities we track, 1 has softer water and 1 has harder. The range nearby runs from 94 mg/L in Powell to 124 in Westerville.

What 97 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 Hilliard

3 people × 75 gallons a day × 5.7 gpg = 1,271 grains a day. A 24,000-grain unit regenerates about every 18 days.

Size it for your household

EPA record for Hilliard's water system

Columbus Public Water System · PWSID OH2504412

1 health-based violation since 2016

Serves about 1,309,468 people from surface water.

Health-based: 1
Monitoring or reporting: 0
Open now: 0

TapWaterData ties Hilliard to this system. EPA's service-area records do not name Hilliard, so check the utility printed on your water bill.

Each dot is one health-based violation, placed at the start of its compliance period.

Contaminant or rule	Violations	Period	Status
Nitrateoften from fertilizer or septic systems	1	2016	Resolved

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 Hilliard water hard?

Somewhat. It measures about 97 mg/L (5.7 grains per gallon), which the USGS classes as moderately hard.

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

About 5.7 gpg. One grain per gallon equals 17.1 mg/L, so 97 mg/L divided by 17.1 gives 5.7.

What size water softener do I need in Hilliard?

For 3 people using 75 gallons each per day, 5.7 gpg works out to about 1,271 grains a day. A 24,000-grain softener covers that with a regeneration about every 18 days.

Has the Hilliard water system had EPA violations?

EPA records show 1 health-based violation for Columbus Public Water System since 2016, involving Nitrate.

Nearby cities

All 108 cities in Ohio

Hardness data: TapWaterData US Water Hardness (utility report, September 30, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.