Grayslake Water Hardness & Quality Report (2026)

The Village of Grayslake, Illinois, operates a public water utility serving approximately 21,097 residents in Lake County. The utility sources its water supply from purchased surface water, drawing from regional surface sources rather than local groundwater. The primary treatment facility employs coagulation to remove sediment, followed by activated carbon and fine sand filtration to reduce turbidity and improve water quality. The utility issues annual Consumer Confidence Reports (CCRs) and maintains compliance monitoring through the EPA's Safe Drinking Water Act framework.

Grayslake's water supply originates in a region underlain by Ordovician and Silurian carbonate bedrock — primarily dolomite and limestone formations. These soluble rock types naturally contribute high concentrations of dissolved calcium and magnesium minerals to surface waters in northern Illinois. The Fox River and other regional surface sources that feed Grayslake's purchased water supply pass through or over these mineral-rich geological formations, resulting in a very hard water supply that reflects the regional hydrogeology.

The very hard water in Grayslake will cause noticeable scale buildup on fixtures, faucets, aerators, and shower heads over time. Appliances such as water heaters, dishwashers, and washing machines are particularly susceptible to mineral accumulation, which reduces efficiency and shortens service life. Residents may experience reduced lather from soaps and detergents and white mineral deposits on glassware and dishes. A water softener is strongly recommended for households seeking to mitigate these effects and extend appliance longevity. Grayslake's water quality data indicates the presence of multiple contaminants, including hexachlorobenzene (HCB), MTBE, and chlorate; residents should consult the utility's annual water quality report or contact the utility at 847-223-8515 for current information.