Forest Park Water Hardness & Quality Report (2026)

The Village of Forest Park Water Department supplies water to the Village of Forest Park, a community of about 14,000 residents in Cook County, Illinois. The primary water source is the vast Lake Michigan, accessed through the Chicago metropolitan intake cribs. This lake water, naturally low in minerals, is supplemented by groundwater drawn from local aquifers. The water undergoes treatment at regional facilities operated by the City of Chicago Bureau of Water Supply or local plants before being distributed by Forest Park's public works department. The Great Lakes basin watershed receives water from glacial melt and precipitation, contributing to the lake's softer character.

Beneath the surface, Forest Park's groundwater taps into aquifers within Pleistocene glacial drift, which sits atop Paleozoic bedrock. This bedrock includes significant Ordovician and Silurian limestone and dolomite formations, such as the Galena-Platteville Group and Maquoketa groups. These carbonate-rich rocks are soluble and, as water percolates through them, they dissolve, releasing calcium and magnesium ions. This mineral leaching is the primary reason why the groundwater component of the supply is harder, despite the softening influence of Lake Michigan.

With its blend of sources, the water's hardness can lead to noticeable scale buildup on plumbing fixtures, appliances like water heaters and dishwashers, and even inside pipes, diminishing their efficiency and lifespan. Homeowners might find themselves needing to flush water heaters more often or dealing with film on glassware. Simple maintenance, such as installing sediment filters and regularly descaling with vinegar, can help manage this. For those experiencing persistent spotting or a film on their skin after showering, installing a water softener is a worthwhile consideration to protect appliances and improve how effectively soaps and detergents lather.