Tigard Water Hardness & Quality Report (2026)

The City of Tigard Water Department serves the Tigard area in Clackamas County, Oregon. The primary drinking water source is the Clackamas River, one of Oregon's highest-quality surface water supplies, withdrawn and treated at the Lake Oswego-Tigard Water Treatment Plant in West Linn. During periods of high summer demand, Tigard supplements its supply with water from two city-owned aquifer storage and recovery (ASR) wells and a native groundwater well, filled during winter months when demand is lower and deployed during peak summer consumption.

The Clackamas River watershed encompasses 940 square miles originating in Mount Hood National Forest, draining through Cascade Range geology dominated by Tertiary volcanic rocks and Quaternary alluvial deposits. This geology produces naturally soft water with low mineral content. During summer, the supplemental ASR and native groundwater wells tap local sedimentary formations containing higher mineral concentrations, creating seasonal variation — the supply shifts from soft to moderately mineralized during peak-demand periods as these two sources blend.

Tigard's water is very soft for most of the year, meaning scale buildup on fixtures and appliances is minimal, soap lathers readily, and water-using appliances experience less mineral-related wear. During summer months when groundwater is blended in, customers may notice a slight increase in mineral content, though the supply remains in the soft to moderately hard range. Most residents will not require a water softener; those sensitive to seasonal hardness may consider point-of-use treatment in summer. Treatment includes biological filtration, conventional filtration, ozone treatment for taste and odor, and hypochlorite disinfection for microbial safety throughout the distribution system.