Hazelwood Water Hardness & Quality Report (2026)

Hazelwood, Missouri, in Saint Louis County northwest of St. Louis, receives its municipal water from Missouri American Water, which draws from the Missouri River — one of the longest rivers in North America, draining 530,000 square miles from the Rocky Mountains across the Great Plains to its confluence with the Mississippi. The Missouri American Water treatment facility processes Missouri River water through coagulation, sedimentation, and filtration before distributing it through the St. Louis metropolitan transmission grid to Hazelwood's suburban neighborhoods.

The hard 201.5 mg/L hardness is a product of the Missouri River's extraordinary multi-state drainage basin. The river flows through Cretaceous Pierre Shale and Niobrara Chalk formations in the Dakotas and Nebraska, crosses Permian carbonate and evaporite terrain in Kansas, and picks up calcium and magnesium from countless tributary systems draining limestone plateaus across Missouri and Iowa. The result is one of the most mineralologically loaded river systems in the country by the time water reaches St. Louis-area intakes.

At 201.5 mg/L, Hazelwood residents deal with consistently hard water throughout the home. Kettles build up scale rapidly, dishwashers leave a persistent white film on glasses and silverware, and showerheads require regular cleaning to maintain full spray. Bathroom grout and tile surfaces accumulate chalky residue that requires acidic cleaners to remove. A water softener is a practical and popular solution for Hazelwood homeowners — it dramatically reduces maintenance across all water-using appliances and improves the feel of shower and laundry water. Without softening, monthly descaling of heating appliances is recommended.