How hard is the water in Manhattan, KS?

Tap water hardness
103mg/L
6.0gpg
Moderately hard

Reported by Manhattan, City of · August 2025

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

Tap water in Manhattan has about 103 mg/L of hardness, which is 6.0 grains per gallon. On the USGS scale that counts as moderately hard. The number comes from Manhattan, City of, dated August 2025.

Manhattan on the hardness scale, with nearby cities
060120180240300360+KS typical 138Emporia: 76 mg/LEmporia 76Fort Riley: 140 mg/LFort Riley 140Lawrence: 142 mg/LLawrence 142Ottawa: 144 mg/LOttawa 144Topeka: 145 mg/LTopeka 145Junction City: 168 mg/LJunction City 168Tonganoxie: 215 mg/LTonganoxie 215Atchison: 294 mg/LAtchison 294Salina: 330 mg/LSalina 330McPherson: 363 mg/LMcPherson 363Manhattan 103mg/L as calcium carbonate060120180240300360+KS 138Emporia: 76 mg/LEmporia 76Fort Riley: 140 mg/LFort Riley 140Lawrence: 142 mg/LLawrence 142Topeka: 145 mg/LTopeka 145Junction City: 168 mg/LJunction C. 168Salina: 330 mg/LSalina 330103 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

Manhattan sits 35 mg/L below the typical Kansas figure of 138. Of the 10 nearest cities we track, 1 has softer water and 9 have harder. The range nearby runs from 76 mg/L in Emporia to 363 in McPherson.

What 103 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 Manhattan

3 people × 75 gallons a day × 6.0 gpg = 1,357 grains a day. A 24,000-grain unit regenerates about every 17 days.

Size it for your household

EPA record for Manhattan's water system

Manhattan, City of · PWSID KS2016112

No health-based violations since 2016

Serves about 54,763 people from groundwater.

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 Manhattan water hard?

Somewhat. It measures about 103 mg/L (6.0 grains per gallon), which the USGS classes as moderately hard.

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

About 6.0 gpg. One grain per gallon equals 17.1 mg/L, so 103 mg/L divided by 17.1 gives 6.0.

What size water softener do I need in Manhattan?

For 3 people using 75 gallons each per day, 6.0 gpg works out to about 1,357 grains a day. A 24,000-grain softener covers that with a regeneration about every 17 days.

Has the Manhattan water system had EPA violations?

EPA records show no health-based violations for Manhattan, City of since 2016.

Nearby cities

All 48 cities in Kansas

Hardness data: TapWaterData US Water Hardness (utility report, August 26, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.