Water Hardness in Joliet, IL
Illinois · 3 zip codes · 21 matched water systems
City avg (weighted): 148 PPM
Dataset updated March 9, 202621 matched water systems in the city rollupIndividual systems and ZIPs can differ. Methodology
Is Joliet, IL Water Hard or Soft?
The displayed hardness for Joliet, IL is 148 PPM (8.7 GPG) from Joliet, classified as moderately hard. The citywide weighted average is 148 PPM.
Water hardness is not a drinking-water safety score. It measures calcium and magnesium minerals, and address-level results can shift by pressure zone, supply blend, building plumbing, or private well.
How this city reading is built
This city reading is a weighted rollup across 21 matched water systems and 3 ZIP codes. Citywide readings are useful for comparison, but individual utility zones and ZIPs can differ.
Hardness is a mineral-content reading, not a drinking-water safety rating. Use it for scale, appliance, and softener decisions; check your utility report or test your tap before sizing treatment equipment. See how we calculate local readings.
Water Systems in Joliet
These systems are matched to Joliet, IL. Citywide readings are useful for comparison, but the system serving a specific address may differ from the city average.
| Water System | Source | Hardness | Pop. Served |
|---|---|---|---|
| Joliet IL1970450 | groundwater | 148 PPM Moderately HardUSGS estimate: 286 PPM | |
| Il American-West Suburban IL1974151 | surface water | 148 PPM Moderately HardUSGS estimate: 207 PPM | |
| Romeoville IL1970900 | groundwater | 148 PPM Moderately HardUSGS estimate: 157 PPM | |
| Plainfield IL1970800 | surface water | 148 PPM Moderately HardUSGS estimate: 224 PPM | |
| New Lenox IL1970700 | surface water | 148 PPM Moderately HardUSGS estimate: 224 PPM |
Zip Codes in Joliet, IL
What This Means For You
Use this city reading as a local planning estimate, not a final treatment specification. Hardness can vary by utility zone, seasonal blend, private well, and building plumbing. Confirm your tap reading with a utility report or home hardness test before sizing equipment.
Know your water hardness?
If you've tested your water or have your utility's CCR report, share your reading to help us improve accuracy for Joliet, IL.
Frequently Asked Questions
How hard is the water in Joliet, IL?
The citywide weighted average water hardness in Joliet, IL is 148 PPM (8.7 GPG), classified as moderately hard. This is based on 21 matched water systems. The gauge highlights Joliet, a verified treated-water system, because individual systems can differ from the citywide average.
Do I need a water softener in Joliet, IL?
With a citywide average hardness of 148 PPM, a water softener is worth considering for homes in Joliet. Confirm your tap reading before sizing equipment.
Is hard water in Joliet, IL safe to drink?
Water hardness itself is a mineral-content reading, not a drinking-water safety rating. Calcium and magnesium are naturally occurring minerals, but you should check your utility's Consumer Confidence Report for contaminant and compliance information.
How many water systems serve Joliet, IL?
Joliet, Illinois is served by 21 matched water systems across 3 zip codes.
Learn More About Your Water
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