South Hill Water Hardness & Quality Report (2026)

South Hill, Washington, an unincorporated community in Pierce County south of Puyallup and east of Tacoma — the most populous unincorporated community in Pierce County and one of the largest in Washington State, a major Pierce County suburban corridor with a rapidly growing diverse population including significant Filipino-American, Korean-American, and Pacific Islander communities — draws its municipal water supply from the Puyallup River Valley alluvial aquifer and Pierce County Quaternary glaciofluvial outwash via the Pierce County Sewer and Water Division. Water hardness in South Hill measures 46 mg/L — classified as very soft.

South Hill's very soft supply reflects the south Puget Sound Pierce County Cascade Range watershed recharge. The South Hill groundwater aquifer is recharged from: the Puyallup River alluvial deposits (Puyallup River carrying Cascade Range snowmelt from Mount Rainier — the Cascade Range andesite and Quaternary volcanic outwash are mafic volcanic, calcium-poor); the Pierce County Vashon Glaciation outwash (Wisconsin Age Vashon Stade glaciofluvial outwash — clean quartz sand and gravel from the Cascades, minimal calcareous content); and the Electron Formation volcanic outwash (Mount Rainier caldera lahar deposits — mafic volcanic, calcium-poor). The dominant calcium-poor Cascade volcanic and glacial outwash terrain produces the very soft 46 mg/L at South Hill.

With hardness at 46 mg/L, South Hill residents enjoy very soft water with essentially no scale challenges. Pierce County Sewer and Water Division consistently delivers water meeting all Washington DOE and EPA Safe Drinking Water Act requirements.