Does Chicago Have Hard Water? Here’s What You Need to Know

Hard water is a common problem in many areas of the United States. If you live in Chicago, you may be wondering if Chicago has hard water.

Chicago has hard water. The average water hardness ranges from 130 to 150 mg/L of calcium carbonate, or 7.6 to 8.8 grains per gallon.

In this blog post, we will discuss Chicago’s water quality, the various factors that contribute to water hardness, and provide some tips on how to soften your water if needed. Keep reading to learn everything you need to know about Chicago’s hard water.

You may be interested in my article about water hardness in other cities.

Does Chicago Have Hard Water?How Hard is Chicago Tap Water

Chicago’s tap water is hard. The average hardness is 148 milligrams per liter (mg/L) as calcium carbonate or 8 grains per gallon (gpg). Throughout the year, Chicago’s water hardness can be as low as 130 parts per million (ppm) and as high as 150 ppm.

Chicago Water Quality – What’s in the city’s tap water

The table below summarizes the water hardness in Chicago and the major cities and towns in the State of Illinois.

CityAverage Hardness Calcium Carbonate mg/LAverage Hardness Grains per GallonZip Code
Chicago148 PPM8 gpg60601 |60602 | 60603 | 60604 | 60605 | 60606 | 60607 | 60608 | 60609 | 60610 | 60611 | 60612 | 60613 | 60614 | 60615 | 60616 | 60617 | 60618 | 60619 | 60620 | 60621 | 60622 | 60623 | 60624 | 60625 |60626 | 60628 | 60629 | 60630 | 60631 | 60632 | 60633 | 60634 | 60636 | 60637 | 60638 | 60639 | 60640 | 60641 | 60642 | 60643 | 60644 | 60645 | 60646 | 60647 | 60649 | 60651 | 60652 | 60653 |60654 | 60655 | 60656 | 60657 | 60659 | 60660 | 60661
Aurora127 PPM7 gpg60502 |60503 | 60504 | 60505 | 60506
Carol Stream418 PPM24 gpg60188
Champaign258 PPM5 gpg61820 | 61821 | 61822
Cicero187 PPM11 gpg60804
Columbus120 PPM7 gpg62236
Crystal Lake137 PPM8 gpg60012 | 60014
Danville191 PPM11 gpg61832 | 61834
Decatur194 PPM11 gpg62521 |62522 | 62523 | 62526
Dekalb188 PPM11 gpg60115
Des Plaines350 PPM18 gpg60016 | 60018
Downers Grove288 PPM17 gpg60515 | 60516
East Peoria250 PPM15 gpg61611
East Saint Louis210 PPM12 gpg62201 | 62203 | 62204 | 62205 | 62206 | 62207
Elgin171 PPM10 gpg60120 | 60123 | 60124
Elmhurst362 PPM21 gpg60126
Elmwood Park218 PPM3 gpg61529 | 60707
Evanston333 PPM20 gpg60201 | 60202 | 60203
Glenview299 PPM18 gpg60025 | 60026
Granite City250 PPM15 gpg62040
Joilet388 PPM23 gpg60431 | 60432 | 60433 | 60435 | 60436
Kankakee196 PPM11 gpg60901
Lombard344 PPM20 gpg60148
Melrose Park222 PPM12 gpg60160 | 60164
Moline210 PPM12 gpg61265
Mount Prospect247 PPM14 gpg60056
Naperville288 PPM17 gpg60540 | 60563 | 60564 | 60565
Oak Lawn222 PPM13 gpg60453
Oak Park212 PPM12 gpg60301 | 60302 | 60304
Orland Park322 PPM19 gpg60462 | 60467
Palatine245 PPM14 gpg60067 | 60074
Peoria250 PPM15 gpg61602 |61603 | 61604 | 61605 | 61606 | 61607 | 61614 | 61615 | 61625
Plainfield280 PPM16 gpg60544  | 60585 | 60586
Rockford308 PPM18 gpg61101 |61102 | 61103 | 61104 | 61107 | 61108 | 61109 | 61112 | 61114
Romeoville395 PPM24 gpg60446
Springfield88 PPM5 gpg62701 |62702 | 62703 | 62704 | 62707 | 62711 | 62712

Learn about water hardness in these cities:

Does New York have hard water?
Does Seattle have hard water?

Does Illinois Have Hard Water

Illinois is a hard water state. The average water hardness in Illinois is around 200 PPM, which is extremely hard. This can cause white deposits on plumbing fixtures and damage to water heaters. Chicago, the most populous city in Illinois, has a water hardness level of 148 PPM. Rockford registers the highest water hardness levels in the state, with 308 PPM (or 18 grains per gallon).

Why Is Chicago Water Hard?

Chicago’s drinking water comes from Lake Michigan. Water flows into Lake Michigan from several rivers, including:

  • Fox-Wolf River
  • Grand River
  • St. Joseph River
  • Kalamazoo River
  • Muskegon River
  • Milwaukee River
  • Menominee River

These rivers pick up hardness (primarily calcium) as they flow towards Lake Michigan. In addition to the hardness contributed by the rivers, the hardness concentration increases as water evaporates from the lake.

Where Does Chicago Water Come from?Chicago Drinking Water Map

The map above shows the location of Chicago’s water supply system.

Chicago’s tap water comes from Lake Michigan. The water treatment process begins when water from the lake, 20-30 feet deep, enters one of the two intake cribs.

Water cribs are offshore structures that collect water from close to the bottom of a lake. The collected water is then conveyed to shore through large diameter tunnels.

Who Provides Water to Chicago

Chicago’s drinking water is supplied by the Bureau of Water Supply. This agency delivers nearly 1 billion gallons of drinking water to residents of Chicago every day.

The Bureau tests for water quality around the clock, every day of the year. The water provided by the Department of Water Management not only meets, but exceeds the current and proposed water quality standards set by organizations such as the United States Environmental Protection Agency and Illinois Pollution Control Board. 

What type of treatment is used to purify Chicago water?Chicago Drinking Water Treatment Process

Chicago’s tap water is purified using the following treatment technologies.

  1. Screening: Water passes through 8 inlet screens to remove debris and solids.
  2. Chlorine: Chlorine is added to disinfect the water.
  3. Aluminum Sulfate and Polymer: These coagulants are added to settle out impurities.
  4. Blended Polyphosphate: Water conditioning is used to coat old pipes and prevent lead leaching.
  5. Activated Carbon: Adsorption is used to remove unpleasant tastes and odors.
  6. Fluoride: Chicago uses this additive to help prevent cavities.


What is hardness

Hardness is a measure of the amount of calcium and magnesium in your water. The higher levels of these minerals, the harder the water. Hard water can cause damage to pipes, deposits on fixtures and even interfere with soap performance.

Problems with hard water

Hard water can have several negative effects, including:

  • Increased plumbing costs due to buildup in pipes and fixtures.
  • Reduced efficiency of water heaters as calcium builds up on the heating element.
  • Soap scum buildup on shower walls and dishes that are difficult to remove.

How Can I Remove Hardness from my Water

Hardness can be reduced by installing a water softener in your home. Water softeners use ion exchange resin to remove calcium and magnesium ions from the water supply, replacing them with sodium ions. This reduces the hardness of your water and prevents damage to pipes, fixtures and appliances.

Water softener for Chicago’s hard water

A water softener is the best way to reduce the hardness in your water. If you live in the Chicago area, you can check out this whole house water softener from FilterWater.

Crystal Quest Whole House Water Softener

crystal quest water softener from Filter Water
Crystal Quest whole house water softener

CRYSTAL QUEST whole house water softeners are simple to use, dependable, and easy to program. They are engineered for maximum filtration and maximum performance with minimum maintenance to deliver trouble free operation for many years with reliable service. All components are the highest quality in the industry and NSF approved.

Check pricing on FilterWater

3-stage filtration process:

  • First stage, 20″ sediment cartridge that removes sediment, silt, sand and dirt. Also extends the life of water softeners and water filters, and prevents damage to control valves.
  • Second stage, Ion exchange mineral tank and brine water conditioner that contains sation resin media
  • Third stage 20″ solid carbon cartridge for removing Volatile Organic Compounds (VOC’s), insecticides, pesticides and industrial solvents.


Model/SKU:CQE-WH-01123, CQE-WH-01124 , CQE-WH-01123S
Controller:Fleck 5600SXT Automatic Backwash Control Valve with LED display.
Flow Rate(Gallon-per-Minute):9 gpm for 1 cubic foot tank, 11 gpm for 1.5 cu.ft, 11-13 gpm for 2 cu.ft.
Tank:White fiberglass tank , available in all Stainless Steel (+$500, inquire).
Bypass Valve:3/4″ or 1″ Stainless Steel
Features:Riser style 1″ internal flow distributor.20″ x 50″ (Diameter x Height) Brine water mineral exchange tank.
Media Life:10+ years.
Filters Life:Sediment pre- and carbon block post filter is recommended to be replaced every 3-6 months


Is Chicago tap water safe to drink?

According to testing by the Chicago Department of Water Management and the Environmental Protection Agency, Chicago’s tap water is safe for drinking.

However, the old water pipes that are still in service for many homes may leach dangerous levels of lead into your water.

Does Chicago’s drinking water taste good?

Chicago’s tap water has a slightly metallic taste due to the minerals in it. The Department of Water Management adds chlorine for disinfection and fluoride for dental health, which can also affect the taste. You can always add a water filter to your tap to remove any unpleasant flavors from your drinking water.

Do I need a water softener if I live in Chicago?

If you have hard water, installing a water softener can reduce the amount of calcium and magnesium in your drinking water. It can also help prevent damage to pipes, fixtures and appliances. However, if you don’t have a problem with hard water, then you may not need a water softener.


Chicago’s tap water is safe for drinking, but it is also hard. The average hardness is 148 ppm. This can lead to problems like soap scum buildup, decreased efficiency of water heaters and increased plumbing costs. The best way to reduce the hardness of your drinking water is to install a water softener in your home. This will ensure that you have clean, healthy drinking water for years to come.

Boch Richard

Richard Boch is a chemical engineer responsible for designing water filtration systems for industrial and residential customers. He has more than 20 years of experience with ion exchange, activated carbon, and reverse osmosis. Richard's expertise has made him a go-to source for municipalities and businesses looking to improve their water quality. When he's not working, Richard enjoys spending time with his wife and two young children.

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