Chatham Water Hardness & Quality Report (2026)

The Village of Chatham Water Department supplies water to Chatham, Illinois, a village of about 12,000 residents south of Springfield. The primary water source is Lake Springfield, a 4,200-acre reservoir formed by damming the Sangamon River. Water from this lake is treated at the Village's West Zone treatment facility. A secondary supply, also treated Lake Springfield water, comes from the Springfield utility system. Daily usage averages around 1 million gallons, distributed through the village and nearby areas.

The watershed feeding Lake Springfield covers 270 square miles, featuring agricultural and urban landscapes within the Sangamon River basin. This area is underlain by Mississippian limestones, specifically the Keokuk and Warsaw Formations, and is covered by glacial outwash sands, gravels, and Pennsylvanian coal measures. Water percolating through these carbonate rocks and fertile soils leaches calcium and magnesium, leading to the hard water characteristic of the region. The geology, influenced by karstic limestone terrains, contributes to the mineral content found in the supply.

This hard water significantly contributes to limescale buildup in appliances like water heaters, dishwashers, and coffee makers, potentially reducing their efficiency by up to 30% and shortening their lifespan. You'll likely find faucet aerators and showerheads clogging within months, requiring frequent cleaning. Plumbing fixtures may develop white deposits, and laundry might appear less bright. For households in Chatham, installing a whole-house water softener is highly recommended to combat these issues. If staining from occasional manganese occurs, iron filters might also be beneficial. Residents are advised to bypass their kitchen taps for drinking water, drinking water, especially if installing a softener.