Rolling Meadows Water Hardness & Quality Report (2026)

Rolling Meadows, Illinois, in Cook County in the northwest suburban Chicago corridor near Schaumburg and Arlington Heights, receives its municipal water from the Rolling Meadows Water Division, purchasing supply from the Northwest Water Commission (NWC), which draws from Lake Michigan via the City of Evanston water treatment plant and the Chicago metropolitan water grid. The NWC distributes Lake Michigan water to numerous northwest Cook County communities, treating and distributing the supply to residential and commercial users throughout the northwest suburbs.

The moderately hard 167.5 mg/L hardness and TDS of 324.6 mg/L reflect Lake Michigan's characteristic water quality with the treatment and distribution influences of the metropolitan Northwest Water Commission system. Lake Michigan receives water from a vast drainage basin encompassing the Wisconsin Driftless and Kettle Moraine carbonate terrain, the Michigan carbonate plain, and the Indiana limestone frontier — contributing moderate calcium and magnesium bicarbonate to the lake's open water. Chicago's water treatment process moderates seasonal variability in lake hardness, and the resulting distributed supply to northwest Cook County communities falls in the consistent moderate range.

At 167.5 mg/L, Rolling Meadows has moderately hard water with familiar household scaling dynamics for the Chicago northwest suburbs. Scale builds gradually in kettles and coffee makers over one to two months, dishwashers benefit from rinse aid, and faucet aerators need quarterly cleaning. Quarterly descaling of heating appliances is the appropriate maintenance schedule. The PFAS level of 5.9 ppt is relatively favorable for a Cook County community — the northwest suburban corridor benefits from Lake Michigan's large water volume, which dilutes PFAS from point sources across the greater Chicago watershed.