The Dalles Water Hardness & Quality Report (2026)

The City of The Dalles Water Company serves about 12,978 residents in The Dalles, Oregon, drawing its supply from surface water sources. The primary source is the Columbia River, supplemented by tributaries such as Mill Creek. Water undergoes treatment at the Wicks Water Treatment Plant, located at 6780 Reservoir Road. Residents can contact the utility at 541-296-5481 or visit their office at 313 Court Street. For those interested in water quality, the Water Quality Laboratory at the treatment plant offers free testing for city customers by appointment.

The region's geology is defined by the Columbia River Basalt Group, a series of Miocene flood basalts that carve the Columbia River Gorge. Beneath these are older Eocene sedimentary layers, including the Clarno Formation and John Day Formation. These volcanic rocks and mineral-rich soils, combined with Eastern Oregon's arid climate, release significant amounts of calcium and magnesium into the river system. This geological makeup naturally contributes to a harder water character for The Dalles' supply, unlike softer waters found in coastal areas.

Homeowners in The Dalles may notice scale buildup on pipes, water heaters, and dishwashers, which can reduce appliance efficiency and shorten their lifespan. Fixtures might develop tell-tale limescale rings, and laundry can feel stiff without adequate soap. Regular descaling of appliances with vinegar and annual flushing of water heaters are helpful maintenance steps. Given the water's mineral content, installing a water softener is often recommended to combat these issues, improve soap lathering, and protect plumbing. Free water quality testing is available at the city lab for routine parameters.