Dearborn Water Hardness & Quality Report (2026)

The City of Dearborn Water and Sewer Department provides drinking water to approximately 100,000 residents in Wayne County, Michigan. Water is sourced from the Detroit River via the Great Lakes Water Authority (GLWA). Raw water is drawn through intakes near the head of Belle Isle, transported approximately 12 miles via tunnel to the GLWA Springwells Water Treatment Plant in Detroit, where it undergoes filtration, disinfection, and chemical adjustment before distribution. The service area covers Dearborn city limits and select adjacent areas in southeast Michigan.

The Detroit River watershed encompasses the transboundary St. Clair-Detroit River system linking Lake Huron, Lake St. Clair, and Lake Erie, with a drainage basin exceeding 200,000 square kilometers shaped by glacial history. Underlying Paleozoic bedrock of the Michigan Basin, including Devonian-age Dundee and Rogers City limestones and Antrim shales, imparts significant mineral content through natural dissolution, yielding a hard supply with elevated calcium and magnesium from carbonate weathering alongside moderate alkalinity.

At 101 mg/L (moderately hard), Dearborn's water promotes moderate scale buildup in pipes, water heaters, dishwashers, and washing machines, reducing efficiency and lifespan. Boilers, faucets, and fixtures accumulate limescale that restricts flow and raises energy costs. Regular vinegar descaling, scale-inhibiting filters, or annual professional maintenance helps mitigate buildup. A water softener is recommended for households experiencing soap scum, dry skin, or spotting on fixtures. Water quality is excellent with no EPA violations; treatment includes coagulation, sedimentation, filtration, and chlorination with pH around 7.5–8.5 and fluoride addition.