Des Moines Water Hardness & Quality Report (2026)

Des Moines Water Works (DMWW) supplies water to central Iowa, including Des Moines and West Des Moines. Sources include alluvial aquifer wells along the Raccoon River, deep Jordan Aquifer wells, and surface water from the Raccoon and Des Moines Rivers treated at DMWW facilities. West Des Moines Water Works (WDMWW) draws approximately 50% from 19 shallow Raccoon River Alluvial wells, 30% from 3 deep Jordan wells, and 20% purchased from DMWW. Treatment involves softening, filtration, disinfection, and fluoridation at plants processing river intakes near the Raccoon River.

The watershed encompasses the Raccoon and Des Moines River basins in Iowa's Des Moines Lobe glacial till plain. Underlying geology features Paleozoic limestone bedrock — Mississippian and Devonian series formations — which constitute the Jordan Aquifer, a confined karstic system rich in carbonates. Alluvial aquifers overlie glacial deposits and river gravels. This limestone-dominated geology dissolves calcium and magnesium into both groundwater and surface supplies during infiltration and river flow, yielding a characteristically hard supply with moderate mineralisation.

At moderate hardness levels, scale buildup occurs noticeably in water heaters, dishwashers, and coffee makers, reducing efficiency and lifespan. Faucet aerators and showerheads may clog, lowering flow rates. Regular vinegar descaling, scale filters, or a water softener are recommended, particularly for high-use households. WDMWW adds fluoride to approximately 1 ppm for dental health. Treatment includes softening with lime, coagulation, sedimentation, filtration, and chlorination; annual Consumer Confidence Reports confirm EPA compliance with action levels for lead and copper not exceeded and no notable violations reported.