Waukegan Water Hardness & Quality Report (2026)

The City of Waukegan Public Water Utility serves Waukegan in Lake County, Illinois, and portions of neighboring communities, delivering approximately 3.5 billion gallons annually through 230 miles of mains. Water is sourced exclusively from Lake Michigan via intakes with a daily capacity of 52 million gallons located 6,200 feet offshore. The utility operates a treatment plant processing raw lake water through coagulation with aluminum sulfate and polymer, sedimentation in settling basins, filtration via layers of gravel, sand, and anthracite, and triple chlorination for disinfection, with continuous online monitoring of turbidity and residuals.

Lake Michigan's watershed encompasses a massive drainage basin fed by rivers and precipitation across multiple states, with water chemistry profoundly shaped by Paleozoic limestone and dolomite formations — including Devonian and Silurian strata — prevalent in the Great Lakes region. Glacial scouring exposed these carbonate rocks, enabling perennial dissolution of calcium and magnesium as water percolates through sediments and bedrock, resulting in a moderately mineralised supply. The offshore intake minimizes nearshore influences but captures the lake's inherent geological signature from basin-wide interactions.

Moderately hard water at 130 mg/L promotes scale buildup in pipes, heaters, and fixtures, reducing efficiency and lifespan — hot water heaters may fail prematurely, costing thousands over a decade. Dishwashers and laundry machines suffer soap scumming and spotting on glassware. Regular vinegar descaling, low-flow aerators, and a water softener are recommended for households with noticeable spotting or high usage. The 2024 CCR confirms full USEPA and state compliance with no violations; pH ranges 7.3–7.6, TDS at 190 mg/L, conductivity 281 µS/cm; arsenic is noted above health guidelines from natural soil and bedrock sources.