How hard is the water in Hilton Head Island, SC?

Tap water hardness
98mg/L
5.7gpg
Moderately hard

Reported by Hilton Head PSD 1 (0720006) · October 2025

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

Hilton Head Island water measures 98 mg/L (5.7 gpg) of hardness, moderately hard by USGS standards. The number comes from Hilton Head PSD 1 (0720006), dated October 2025.

Hilton Head Island on the hardness scale, with nearby cities
060120180240300360+SC typical 32Summerville: 26 mg/LSummerville 26Beaufort: 41 mg/LBeaufort 41Port Royal: 43 mg/LPort Royal 43Hardeeville: 43 mg/LHardeeville 43Bluffton: 44 mg/LBluffton 44Hanahan: 51 mg/LHanahan 51North Charleston: 53 mg/LNorth Charleston 53Charleston: 57 mg/LCharleston 57James Island: 58 mg/LJames Island 58Mount Pleasant: 59 mg/LMount Pleasant 59Hilton Head Island 98mg/L as calcium carbonate060120180240300360+SC 32Beaufort: 41 mg/LBeaufort 41Port Royal: 43 mg/LPort Royal 43Hardeeville: 43 mg/LHardeeville 43Bluffton: 44 mg/LBluffton 44Charleston: 57 mg/LCharleston 57James Island: 58 mg/LJames Isla. 5898 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 98 mg/L, Hilton Head Island is 66 mg/L above the typical South Carolina figure of 32. None of the 10 nearest cities we track has harder water. The range nearby runs from 26 mg/L in Summerville to 59 in Mount Pleasant.

What 98 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 Hilton Head Island

3 people × 75 gallons a day × 5.7 gpg = 1,282 grains a day. A 24,000-grain unit regenerates about every 18 days.

Size it for your household

EPA record for Hilton Head Island's water system

Hilton Head PSD 1 (0720006) · PWSID SC0720006

No health-based violations since 2016

Serves about 25,558 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 Hilton Head Island water hard?

Somewhat. It measures about 98 mg/L (5.7 grains per gallon), which the USGS classes as moderately hard.

What is the water hardness in Hilton Head Island in grains per gallon?

About 5.7 gpg. One grain per gallon equals 17.1 mg/L, so 98 mg/L divided by 17.1 gives 5.7.

What size water softener do I need in Hilton Head Island?

For 3 people using 75 gallons each per day, 5.7 gpg works out to about 1,282 grains a day. A 24,000-grain softener covers that with a regeneration about every 18 days.

Has the Hilton Head Island water system had EPA violations?

EPA records show no health-based violations for Hilton Head PSD 1 (0720006) since 2016.

Nearby cities

All 58 cities in South Carolina

Hardness data: TapWaterData US Water Hardness (utility report, October 15, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.