Detroit Water Hardness & Quality Report (2026)

The Detroit Water and Sewerage Department (DWSD) serves approximately 4.3 million residents across Wayne, Oakland, Macomb, and parts of Washtenaw counties in southeast Michigan. Water is sourced from the Detroit River via the Great Lakes Water Authority (GLWA), which operates water treatment facilities formerly known as DWSD's Springwells and Water Works Park plants. Raw water is drawn through intakes in the Detroit River, a connecting channel between Lake Huron and Lake Erie, then treated and distributed through an extensive network of pipes and reservoirs.

The Detroit River watershed spans the international boundary, fed by Lake St. Clair and upstream Great Lakes inflows, with a drainage area exceeding 200,000 square kilometers. Underlying geology features Devonian limestone and dolomite bedrock, overlain by Pleistocene glacial till, which dissolves slowly into surface waters contributing elevated calcium and magnesium. This carbonate-dominated terrain imparts a hard character to the supply, with naturally elevated mineral content from rock weathering and minimal buffering from softer siliceous inputs.

Hard water leads to moderate to significant scale buildup in pipes, water heaters, dishwashers, and washing machines — water heaters may fail up to 30% sooner — with soap scum on fixtures and increased detergent use common. Regular deliming of appliances, drain screens, and flushing water heaters help extend equipment life; a salt-based ion exchange softener is recommended to exchange minerals for sodium, preventing buildup and extending appliance lifespan. DWSD's 2023 Water Quality Report confirms compliance with EPA and Michigan standards; the 90th percentile lead level was 9 ppb from homes with lead service lines, aided by corrosion inhibitors; treatment includes coagulation, sedimentation, filtration, chloramine disinfection, and orthophosphate for pipe protection.