Water Hardness in Illinois Cities

Water Hardness in Illinois Cities

Water hardness is defined by the level of calcium and magnesium ions in the water. This characteristic can fluctuate across Illinois, as various parts of the state exhibit different water hardness levels due to their distinct geological features and sources of water.

In Illinois, water hardness can vary from soft to very hard, contingent upon the specific location in the state. Northern Illinois, particularly areas closer to Lake Michigan, typically have softer water as a result of the large freshwater source’s influence. However, southern and central parts of Illinois might have harder water due to the local bedrock and groundwater that can contain higher concentrations of dissolved minerals.

The actual water hardness measurements in Illinois cities can shed light on the specific water conditions. Water hardness indictors are prone to changes, but numerous communities in Illinois are known to have moderately hard to very hard water levels. These hardness levels can impact the taste of water, the performance of cleaning products like soaps, and have consequences on household water-using appliances.

The water hardness levels in the state of Illinois show variation across different cities, with measurements given in parts per million (ppm) and grains per gallon (gpg). Cities such as Lockport and Batavia exhibit high hardness levels of up to 667.6 ppm, 39 gpg, and 428.0 ppm, 25 gpg, respectively. On the contrary, Springfield has a relatively lower level at 110.0 ppm, 6.43 gpg. Moreover, several cities like Chicago, Naperville, and Cicero have hardness levels measured at 141.7 ppm, 8.24 gpg. While cities such as Peoria, Rockford, and Joliet along with others did not have available data.

City Hardness ppm (mg/L) Hardness gpg Information Source Notes
Chicago 141.7 8.3 Link Lake Michigan
Aurora 135.0 8.0 Link
Joliet n/a n/a Link Currently groundwater, will be from Chicago starting in 2030
Naperville 141.7 8.3 Link Purchases from Chicago
Rockford n/a n/a Link
Elgin n/a n/a Link
Springfield 110.0 6.4 Link
Peoria n/a n/a Link
Champaign n/a n/a Link
Waukegan 130.0 7.6 Link Lake Michigan
Cicero 141.7 8.3 Link Purchases from Chicago
Bloomington n/a n/a Link
Evanston 139.0 8.1 Link Lake Michigan
Schaumburg 141.7 8.3 Link Purchases from Chicago
Arlington Heights 139.0 8.1 Link Purchases from Evanston
Bolingbrook n/a n/a Link
Decatur n/a n/a Link Lake Decatur
Skokie 139.0 8.1 Link Purchases from Evanston
Palatine 139.0 8.1 Link Purchases from Evanston
Des Plaines 141.7 8.3 Link Purchases from Chicago
Orland Park 141.7 8.3 Link Purchases from Chicago
Oak Lawn 141.7 8.3 Link Purchases from Chicago
Berwyn 141.7 8.3 Link Purchases from Chicago
Mount Prospect 141.7 8.3 Link Purchases from Chicago
Tinley Park 141.7 8.3 Link Purchases from Chicago
Normal n/a n/a Link
Oak Park 141.7 8.3 Link Purchases from Chicago
Wheaton 141.7 8.3 Link Purchases from Chicago
Hoffman Estates 141.7 8.3 Link Purchases from Chicago via Northwest Suburban
Downers Grove 144.0 8.4 Link Purchases from Chicago thru DuPage Water Commission, used Elmhurst’s number
Glenview 142.0 8.2 Link Lake Michigan via Wilmette
Plainfield 141.7 8.3 Link Purchases from Chicago
Elmhurst 144.0 8.4 Link Purchases from Chicago thru DuPage Water Commission
Lombard 144.0 8.4 Link Purchases from Chicago thru DuPage Water Commission, used Elmhurst’s number
Buffalo Grove 137.0 8.0 Link Lake Michigan
Moline n/a n/a Link Sources form Mississippi also sources to Silvis
Belleville n/a n/a Link
Bartlett 144.0 8.4 Link Purchases from Chicago thru DuPage Water Commission, used Elmhurst’s number
DeKalb 119.8 7.0 Link Groundwater that is softened during treatment
Romeoville n/a n/a Link
Crystal Lake n/a n/a Link
Carol Stream 141.7 8.3 Link Purchases from Chicago
Quincy n/a n/a Link Sources from Mississippi River
Park Ridge 141.7 8.3 Link Purchases from Chicago
Urbana n/a n/a Link
Streamwood 141.7 8.3 Link Purchases from Chicago
Wheeling 139.0 8.1 Link Purchases from Evanston
Carpentersville n/a n/a Link
Hanover Park 141.7 8.3 Link Purchases from Chicago
Rock Island n/a n/a Link
Addison 144.0 8.4 Link Purchases from Chicago thru DuPage Water Commission, used Elmhurst’s number
Oswego 256.0 15.0 Link
Calumet City 141.7 8.3 Link Sources from Chicago
Northbrook n/a n/a Link Lake Michigan directly, Not Chicago
Woodridge 144.0 8.4 Link Purchases from Chicago thru DuPage Water Commission, used Elmhurst’s number
St. Charles n/a n/a Link
Glendale Heights 144.0 8.4 Link Purchases from Chicago thru DuPage Water Commission, used Elmhurst’s number
O’Fallon n/a n/a Link Mississippi River via E. St. Louis
Elk Grove Village 141.7 8.3 Link Purchases from Chicago via Northwest Suburban
Mundelein n/a n/a Link Lake Michigan
Pekin n/a n/a Link
Gurnee n/a n/a Link Lake Michigan via Lake Bluff
Niles 139.0 8.1 Link Receives via Morton Grove
Highland Park 132.5 7.8 Link Lake Michigan, separate intake from Chicago proper
North Chicago n/a n/a Link Lake Michigan, separate intake from Chicago proper
Algonquin n/a n/a Link
Galesburg n/a n/a Link
Lake in the Hills n/a n/a Link
Burbank 141.7 8.3 Link Purchases from Chicago
Danville n/a n/a Link
Glen Ellyn 144.0 8.4 Link Purchases from Chicago thru DuPage Water Commission, used Elmhurst’s number
Lansing n/a n/a Link Purchases from Hammond IN, which doesn’t report
Huntley n/a n/a Link
Wilmette 142.0 8.2 Link Lake Michigan
Granite City n/a n/a Link
New Lenox 141.7 8.3 Link Purchases from Chicago
McHenry n/a n/a Link
Round Lake Beach n/a n/a Link Lake Michigan via Lake Bluff
Chicago Heights n/a n/a Link Purchases from Hammond IN, which doesn’t report
Oak Forest 141.7 8.3 Link Purchases form Chicago
Vernon Hills n/a n/a Link Lake Michigan via Lake Bluff
Lockport 667.6 39.0 Link Used City of Lockport CCR Document on the linked page
Batavia 428.0 25.0 Link
Woodstock n/a n/a Link
Alton n/a n/a Link
West Chicago n/a n/a Link Well water, mentions they treat to reduce hardness but don’t provide values
Edwardsville n/a n/a Link
Belvidere 402.3 23.5 Link
Morton Grove 139.0 8.1 Link Purchases from Evanston
Homer Glen 141.7 8.3 Link Purchases from Chicago
Zion n/a n/a Link Purchases from Decatur
Collinsville n/a n/a Link
Melrose Park 141.7 8.3 Link Purchases from Chicago
Westmont 144.0 8.4 Link Purchases from Chicago thru DuPage Water Commission, used Elmhurst’s number
Elmwood Park 141.7 8.3 Link Purchases from Chicago
Kankakee n/a n/a Link
South Elgin n/a n/a Link
Lisle 144.0 8.4 Link Purchases from Chicago thru DuPage Water Commission, used Elmhurst’s number
Rolling Meadows 141.7 8.3 Link Purchases from Chicago via Northwest Suburban
Freeport n/a n/a Link
Top 100 Illinois cities by population and their reported water hardness
ppm = Parts Per Million
mg/L = Milligrams Per Liter
gpg = Grains Per Gallon

Hard water can cause issues such as mineral buildup in plumbing and appliances, reduce the efficacy of soaps and detergents, and affect the taste of the water. A tried and true solution is the use of a water softener. A water softener, like the ones from DROP, could be a worthwhile investment.

These devices work by replacing the calcium and magnesium ions that cause hardness with sodium ions, resulting in softer water. With innovative features, easy installation, and efficient operation, DROP smart water softeners provide a solution to hard water issues, extending the lifespan of appliances, improving water taste, enhancing soap effectiveness, reducing scale build-up, and increasing the overall water efficiency in your home.

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