Hard water in Washington, IL
Calculated from the utility's calcium and magnesium results · August 2025
- IL typical
- 139 mg/L
- EPA health violations since 2016
- 0
- Softener for 3 people
- 24k grain
- Data
- Calculated from utility data
The water in Washington carries roughly 230 mg/L of dissolved calcium and magnesium, or 13.4 grains per gallon. That is very hard water. TapWaterData worked it out from the calcium and magnesium levels the local utility reports (August 2025). Reports for this system disagree, with values from 230 to 291 mg/L.
Washington sits 91 mg/L above the typical Illinois figure of 139. Of the 10 nearest cities we track, 3 have softer water and 7 have harder. The range nearby runs from 89 mg/L in Bloomington to 401 in Canton.
What 230 mg/L means at home
Scale forms fast here. Kettles and coffee makers need regular descaling, and showerheads clog unless you clean them.
Tank water heaters collect mineral sediment that insulates the water from the burner, so flushing the tank matters more than usual.
Dishes and glass shower doors spot easily. Soap scum and a dull film on hair or laundry are common complaints.
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
At 230 mg/L most of the trouble is scale, and only a few things deal with it.
Ion-exchange water softener
The standard whole-house fix. It swaps calcium and magnesium for sodium or potassium and needs salt plus a drain. Size it with the calculator below.
Salt-free conditioner
No salt and no drain line. It changes how minerals form scale instead of removing them, so water still tests hard.
Reverse osmosis or carbon filter
Under-sink reverse osmosis removes minerals from drinking water only. Plain carbon filters improve taste but do not soften.
3 people × 75 gallons a day × 13.4 gpg = 3,024 grains a day. A 24,000-grain unit regenerates about every 7 days.
EPA record for Washington's water system
No health-based violations since 2016
Serves about 14,793 people from groundwater.
- Health-based
- 0
- Monitoring or reporting
- 2
- Open now
- 0
EPA lists this system as serving Washington.
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 Washington water hard?
Yes. It measures about 230 mg/L (13.4 grains per gallon), which the USGS classes as very hard.
What is the water hardness in Washington in grains per gallon?
About 13.4 gpg. One grain per gallon equals 17.1 mg/L, so 230 mg/L divided by 17.1 gives 13.4.
What size water softener do I need in Washington?
For 3 people using 75 gallons each per day, 13.4 gpg works out to about 3,024 grains a day. A 24,000-grain softener covers that with a regeneration about every 7 days.
Has the Washington water system had EPA violations?
EPA records show no health-based violations for Washington since 2016. There were also 2 monitoring or reporting violations, which are about late or missing tests and notices.
Nearby cities
- East Peoria361 mg/LVery hard
- Morton170 mg/LHard
- Peoria272 mg/LVery hard
- Bartonville283 mg/LVery hard
- Pekin361 mg/LVery hard
- Normal327 mg/LVery hard
- Bloomington89 mg/LModerately hard
- Canton401 mg/LVery hard
- Lincoln222 mg/LVery hard
- Streator253 mg/LVery hard
Hardness data: TapWaterData US Water Hardness (calculated from utility data, August 13, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.