Moline Water Hardness & Quality Report (2026)

The City of Moline Water Division operates the Moline Water Treatment Plant, a lime softening facility treating water from the Mississippi River in Rock Island County, Illinois. The utility serves over 17,000 homes and businesses with an average daily demand exceeding 5 million gallons. The plant pumps and meters treated water throughout the city's distribution system, and publishes an annual Consumer Confidence Report each July detailing compliance with over 100 contaminants monitored under Illinois EPA certification.

The Mississippi River watershed flows southward through Paleozoic formations including the Galena-Platteville Group and Maquoketa Formation — carbonate rock layers deposited during the Ordovician and Silurian periods that weather to release calcium and magnesium, producing a hard supply. Alluvial deposits and glacial till in the Quad Cities region add to the mineral load, while Devonian and Carboniferous limestones, dolomites, and sandstones from ancient shallow seas further shape water chemistry. This geology consistently delivers mineralised water requiring softening treatment at the plant.

Hard water causes limescale buildup in pipes, water heaters, dishwashers, and washing machines, with white deposits on fixtures and spots on glassware increasing energy costs by up to 20–30%. Regular deliming of appliances and a water softener are recommended to prevent scaling and extend equipment life; the lime softening process at the treatment plant removes approximately half the source hardness. Nitrate has been detected above health guidelines from fertilizer runoff and is regulated to prevent blue baby syndrome. The utility complies with lead and copper rules via corrosion control, with pH managed during treatment.