Lake Michigan

Great Lake · Midwest

Serves 29 cities in our database · ~5,826,136 residents

205
Avg Hardness (PPM)
1.2
Avg PFAS (ppt)
7.4
Avg Lead (ppb)
29
Cities Served
Soft
0Slightly
60Moderate
120Hard
180Very Hard
250Extreme
400+
205 PPM Very Hard
CONTAMINANT LEVELS Hardness 205 PPM TDS 308 PPM PFAS 1.2 ppt Lead 7.4 ppb Chlorine 1.1 mg/L Nitrate 0.4 mg/L

About Lake Michigan

The third-largest Great Lake supplies drinking water to over 10 million people across the Midwest, including Chicago. The water is naturally soft but requires treatment for seasonal algae and industrial runoff.

Geography & Hydrology

Lake Michigan spans 22,400 square miles with an average depth of 279 feet. Water enters from over 100 tributaries and the retention time is approximately 62 years — meaning water that enters today will remain in the lake until roughly 2088.

How Lake Michigan Water Is Treated

Most Lake Michigan water treatment plants use conventional treatment: coagulation, sedimentation, sand filtration, and chlorine disinfection. Chicago adds fluoride and phosphate for corrosion control. The naturally low mineral content means soft water for most cities.

Across the 29 cities we track, water from Lake Michigan averages 205 PPM hardness (Very Hard), ranging from 137 to 350 PPM. This is very hard water - most homeowners benefit from a water softener.

Current Challenges

Seasonal algae blooms, microplastics from urban runoff, legacy industrial contamination, invasive species affecting water quality, and PFAS from military installations around the basin.

Cities Supplied by Lake Michigan

Water quality varies by city due to local treatment, distribution infrastructure, and source blending.

Chicago, IL

140 PPM · Hard 2,746,388 residents

Milwaukee, WI

140 PPM · Hard 626,000 residents

Grand Rapids, MI

137 PPM · Hard 273,005 residents

Grand Rapids Downtown, MI

300 PPM · Extremely Hard 273,005 residents

Joliet, IL

279 PPM · Extremely Hard 160,000 residents

Naperville South, IL

310 PPM · Extremely Hard 156,406 residents

Elgin, IL

191 PPM · Very Hard 114,797 residents

Green Bay, WI

166 PPM · Hard 107,369 residents

Racine, WI

139 PPM · Hard 105,100 residents

Kenosha, WI

143 PPM · Hard 99,218 residents

Waukegan, IL

165 PPM · Hard 87,149 residents

Cicero, IL

150 PPM · Hard 83,000 residents

Hammond, IN

171 PPM · Hard 78,384 residents

Schaumburg, IL

175 PPM · Hard 75,750 residents

Evanston, IL

140 PPM · Hard 74,486 residents

Bolingbrook, IL

350 PPM · Extremely Hard 73,978 residents

Arlington Heights, IL

290 PPM · Extremely Hard 73,320 residents

Wyoming, MI

170 PPM · Hard 72,125 residents

Palatine, IL

300 PPM · Extremely Hard 70,875 residents

Waukesha, WI

196 PPM · Very Hard 70,718 residents

Orland Park, IL

320 PPM · Extremely Hard 58,862 residents

Oak Park, IL

145 PPM · Hard 54,583 residents

Oak Park South, IL

140 PPM · Hard 54,583 residents

Wheaton, IL

310 PPM · Extremely Hard 53,970 residents

Sheboygan, WI

170 PPM · Hard 49,931 residents

Wauwatosa, WI

140 PPM · Hard 49,064 residents

Manitowoc, WI

165 PPM · Hard 34,500 residents

Brookfield, WI

190 PPM · Very Hard 29,070 residents

Libertyville, IL

310 PPM · Extremely Hard 20,500 residents

Recommended for Lake Michigan Water

Based on average water quality across 29 cities supplied by Lake Michigan.

Water Softener SpringWell SS1 ~$1,495 Scale Remover CLR Calcium Lime Rust ~$10 Test Your Tap Home Water Test Kit ~$30

Affiliate disclosure: we may earn a commission on purchases. Recommendations based on water quality data.

Frequently Asked Questions

Is Lake Michigan water safe to drink?
Water from Lake Michigan meets EPA safety standards in all served cities. Contaminant levels are within legal limits, though additional filtration can improve quality beyond legal minimums.
Why is Lake Michigan water so hard?
Lake Michigan water picks up dissolved calcium and magnesium from the geological formations along its path. At 205 PPM average, this makes it very hard.
How many people drink Lake Michigan water?
Lake Michigan supplies drinking water to 29 cities in our database, serving approximately 5,826,136 residents. The largest cities include Chicago, IL; Milwaukee, WI; Grand Rapids, MI.
Do I need a water filter for Lake Michigan water?
A water softener is more important than a filter here. At 205 PPM average hardness, scale buildup is the primary concern. A filter is beneficial for drinking water quality.