How hard is the water in Oak Island, NC?

Tap water hardness
61mg/L
3.6gpg
Moderately hard

Reported by Brunswick County Water System · July 2025

NC typical
31 mg/L
EPA health violations since 2016
0
Softener for 3 people
24k grain
Data
Utility report

The water in Oak Island carries roughly 61 mg/L of dissolved calcium and magnesium, or 3.6 grains per gallon. That is moderately hard water. The number comes from Brunswick County Water System, dated July 2025.

Oak Island on the hardness scale, with nearby cities
060120180240300360+NC typical 31Wilmington: 21 mg/LWilmington 21Hampstead: 27 mg/LHampstead 27St. James: 49 mg/LSt. James 49Boiling Spring Lakes: 49 mg/LBoiling Spring Lakes 49Shallotte: 49 mg/LShallotte 49Leland: 49 mg/LLeland 49Holly Ridge: 52 mg/LHolly Ridge 52Jacksonville: 52 mg/LJacksonville 52Half Moon: 52 mg/LHalf Moon 52Carolina Beach: 180 mg/LCarolina Beach 180Oak Island 61mg/L as calcium carbonate060120180240300360+NC 31Wilmington: 21 mg/LWilmington 21St. James: 49 mg/LSt. James 49Boiling Spring Lakes: 49 mg/LBoiling Sp. 49Shallotte: 49 mg/LShallotte 49Leland: 49 mg/LLeland 49Carolina Beach: 180 mg/LCarolina B. 18061 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

At 61 mg/L, Oak Island is 30 mg/L above the typical North Carolina figure of 31. Of the 10 nearest cities we track, 9 have softer water and 1 has harder. The range nearby runs from 21 mg/L in Wilmington to 180 in Carolina Beach.

What 61 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 Oak Island

3 people × 75 gallons a day × 3.6 gpg = 801 grains a day. A 24,000-grain unit regenerates about every 29 days.

Size it for your household

EPA record for Oak Island's water system

Oak Island, Town of · PWSID NC0410020

No health-based violations since 2016

Serves about 26,924 people from surface water.

Health-based
0
Monitoring or reporting
5
Open now
0

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

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 Oak Island water hard?

Somewhat. It measures about 61 mg/L (3.6 grains per gallon), which the USGS classes as moderately hard.

What is the water hardness in Oak Island in grains per gallon?

About 3.6 gpg. One grain per gallon equals 17.1 mg/L, so 61 mg/L divided by 17.1 gives 3.6.

What size water softener do I need in Oak Island?

For 3 people using 75 gallons each per day, 3.6 gpg works out to about 801 grains a day. A 24,000-grain softener covers that with a regeneration about every 29 days.

Has the Oak Island water system had EPA violations?

EPA records show no health-based violations for Oak Island, Town of since 2016. There were also 5 monitoring or reporting violations, which are about late or missing tests and notices.

Nearby cities

All 101 cities in North Carolina

Hardness data: TapWaterData US Water Hardness (utility report, July 28, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.