How hard is the water in Northlake, IL?

Tap water hardness
104mg/L
6.1gpg
Moderately hard

Reported by Leyden TWSP Water District · May 2025

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

Tap water in Northlake has about 104 mg/L of hardness, which is 6.1 grains per gallon. On the USGS scale that counts as moderately hard. The number comes from Leyden TWSP Water District, dated May 2025.

Northlake on the hardness scale, with nearby cities
060120180240300360+IL typical 139Villa Park: 99 mg/LVilla Park 99Melrose Park: 103 mg/LMelrose Park 103Berkeley: 104 mg/LBerkeley 104Franklin Park: 104 mg/LFranklin Park 104Bellwood: 104 mg/LBellwood 104River Grove: 104 mg/LRiver Grove 104Schiller Park: 104 mg/LSchiller Park 104Bensenville: 104 mg/LBensenville 104Elmhurst: 110 mg/LElmhurst 110Maywood: 229 mg/LMaywood 229Northlake 104mg/L as calcium carbonate060120180240300360+IL 139Melrose Park: 103 mg/LMelrose Pa. 103Berkeley: 104 mg/LBerkeley 104Franklin Park: 104 mg/LFranklin P. 104Bellwood: 104 mg/LBellwood 104River Grove: 104 mg/LRiver Grove 104Elmhurst: 110 mg/LElmhurst 110104 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

Northlake sits 35 mg/L below the typical Illinois figure of 139. Of the 10 nearest cities we track, 2 have softer water and 2 have harder. The range nearby runs from 99 mg/L in Villa Park to 229 in Maywood.

What 104 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 Northlake

3 people × 75 gallons a day × 6.1 gpg = 1,368 grains a day. A 24,000-grain unit regenerates about every 17 days.

Size it for your household

EPA record for Northlake's water system

Northlake · PWSID IL0314710

No health-based violations since 2016

Serves about 12,840 people from surface water.

Health-based
0
Monitoring or reporting
3
Open now
0

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

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 Northlake water hard?

Somewhat. It measures about 104 mg/L (6.1 grains per gallon), which the USGS classes as moderately hard.

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

About 6.1 gpg. One grain per gallon equals 17.1 mg/L, so 104 mg/L divided by 17.1 gives 6.1.

What size water softener do I need in Northlake?

For 3 people using 75 gallons each per day, 6.1 gpg works out to about 1,368 grains a day. A 24,000-grain softener covers that with a regeneration about every 17 days.

Has the Northlake water system had EPA violations?

EPA records show no health-based violations for Northlake since 2016. There were also 3 monitoring or reporting violations, which are about late or missing tests and notices.

Nearby cities

All 192 cities in Illinois

Hardness data: TapWaterData US Water Hardness (utility report, May 13, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.