Pullman Water Hardness & Quality Report (2026)

Pullman, Washington, the Whitman County seat — a major southeast Washington university city (Pullman is the Whitman County seat and home of Washington State University — a major Pac-12 land-grant research university, one of the flagship universities of Washington State; Pullman is also adjacent to Moscow, Idaho — home of the University of Idaho — forming one of the most unusual 'college town' pairs in the United States, two major universities within 8 miles of each other across the state line), a diverse Whitman County community with a significant South Asian-American, Chinese-American, and international student population, famous for the Palouse region's dramatic rolling wheat fields (the Palouse is one of the most productive dryland wheat farming regions in the world — the steep loess hills produce distinctive scenery), and a major Washington State agricultural and research hub — draws its municipal water supply from the Columbia River Basalt aquifer via the City of Pullman Water Division. Water hardness in Pullman measures 81.5 mg/L — classified as moderately soft.

Pullman's moderate softness reflects the Palouse Hills Columbia River Basalt aquifer geology. The Columbia River Basalt Group at Pullman–Whitman County (Miocene calcareous-moderate basaltic flows — the thick Palouse Hills basalt; less calcareous than the eastern plains basalt zones). City of Pullman treatment produces the moderate 81.5 mg/L.

With hardness at 81.5 mg/L, Pullman residents enjoy moderately soft water. City of Pullman Water Division consistently delivers water meeting all Washington State DOE and EPA Safe Drinking Water Act requirements.