Tri-Cities Water Hardness & Quality Report (2026)

The Tri-Cities Water Utilities serve Kennewick, Pasco, and Richland in Benton and Franklin Counties, Washington, providing potable water to over 100,000 residents across a 150-square-mile area. Primary sources include the Columbia River for surface water, treated at the Howard A. Hanson Water Treatment Plant in Richland and the Kennewick Water Treatment Plant. Groundwater supplements from over 20 wells tap the Ringold Aquifer and shallow alluvial aquifers, managed by the City of Kennewick Water Division and Richland Water Utilities; the utilities blend river and well water seasonally to meet demand.

The Columbia River watershed, spanning the Cascade Range to the Columbia Plateau, shapes the supply through basalt flows and glacial outwash. The Wanapum Basalt and Ringold Formation dominate local geology, with volcanic rocks leaching minerals during infiltration and alluvial gravels filtering river water into aquifers. This geology imparts a hard character to both surface and groundwater, with elevated calcium and magnesium derived from basalt dissolution and evaporite influences in the sedimentary layers.

Hard water leads to scale buildup in pipes, water heaters, dishwashers, and washing machines, reducing efficiency and lifespan. Soap lathering is poor, leaving films on skin, hair, and laundry. Maintenance tips include regular descaling of appliances, installing sediment filters, and flushing hot water tanks annually; a water softener is recommended, especially in areas with higher well water blending. Water quality meets EPA standards; pH is typically 7.5–8.5; lead and copper comply under LCR rules with corrosion control via pH adjustment and orthophosphate; no notable PFAS detections; treatment involves coagulation, sedimentation, filtration, and chlorine disinfection.