Durham, NC water hardness

Tap water hardness
30mg/L
1.7gpg
Soft

Reported by Durham, City of · September 2025

NC typical
31 mg/L
EPA health violations since 2016
0
Data
Utility report

Tap water in Durham has about 30 mg/L of hardness, which is 1.7 grains per gallon. On the USGS scale that counts as soft. The number comes from Durham, City of, dated September 2025.

Durham on the hardness scale, with nearby cities
060120180240300360+NC typical 31Raleigh: 25 mg/LRaleigh 25Rolesville: 25 mg/LRolesville 25Apex: 27 mg/LApex 27Chapel Hill: 30 mg/LChapel Hill 30Morrisville: 30 mg/LMorrisville 30Carrboro: 30 mg/LCarrboro 30Cary: 33 mg/LCary 33Mebane: 40 mg/LMebane 40Holly Springs: 41 mg/LHolly Springs 41Wake Forest: 106 mg/LWake Forest 106Durham 30mg/L as calcium carbonate060120180240300360+NC 31Raleigh: 25 mg/LRaleigh 25Apex: 27 mg/LApex 27Chapel Hill: 30 mg/LChapel Hill 30Morrisville: 30 mg/LMorrisville 30Carrboro: 30 mg/LCarrboro 30Cary: 33 mg/LCary 3330 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

Durham sits close to the typical North Carolina figure of 31 mg/L. Of the 10 nearest cities we track, 3 have softer water and 4 have harder. The range nearby runs from 25 mg/L in Raleigh to 106 in Wake Forest.

What 30 mg/L means at home

Soap and shampoo lather with very little product. Kettles and showerheads stay mostly free of white crust.

Some people notice that soap feels slow to rinse off in soft water. That slippery feel is normal and harmless.

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

Nothing, as far as hardness goes. At 30 mg/L a softener would have almost nothing to remove.

Carbon filter

If the water tastes of chlorine, a pitcher or faucet carbon filter takes care of that. It does not change hardness.

EPA record for Durham's water system

Durham, City of · PWSID NC0332010

No health-based violations since 2016

Serves about 333,490 people from surface water.

Health-based
0
Monitoring or reporting
4
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 Durham water hard?

No. It measures about 30 mg/L (1.7 grains per gallon), which the USGS classes as soft.

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

About 1.7 gpg. One grain per gallon equals 17.1 mg/L, so 30 mg/L divided by 17.1 gives 1.7.

Has the Durham water system had EPA violations?

EPA records show no health-based violations for Durham, City of since 2016. There were also 4 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, September 18, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.