Vernon Hills Water Hardness & Quality Report (2026)

Vernon Hills Water Company serves approximately 20,848 residents in Vernon Hills, Illinois, within Lake County. The utility purchases surface water primarily from Lake Michigan, treated at regional facilities managed by Lake County Public Works. Distribution systems serve the village and surrounding zones in northern Lake County, near the Wisconsin border. Contact is available at 847-367-3700 or via Austin McFarlane at 847-377-7500. The supply originates from the Lake Michigan watershed, fed by rivers including the Fox and Des Plaines.

Underlying geology features Silurian-age Niagaran dolomite and limestone formations, part of the broader Great Lakes carbonate platform from the Paleozoic era. Glacial deposits from the Wisconsinan glaciation shape the surficial hydrology, with surficial glacial outwash sands overlying the bedrock aquifer system. Water chemistry reflects moderate mineralisation from dolomite dissolution, producing a hard supply typical of northern Illinois lake-influenced sources rather than the very hard groundwater of southern karst aquifers.

Scale buildup accelerates at this hardness level in water heaters, dishwashers, and washing machines, shortening appliance life and raising energy costs through reduced efficiency. Water heaters often need anode rod replacements every 2–3 years and full unit replacements every 8–12 years. Maintenance includes annual flushing of heaters, installing scale-inhibiting filters, and using vinegar descaling for fixtures. A whole-house softener is recommended to mitigate spotting on dishes and glassware. Annual Consumer Confidence Reports from Lake County Public Works confirm EPA compliance; the supply undergoes conventional treatment including coagulation, sedimentation, filtration, and chlorination.