Grants Pass Water Hardness & Quality Report (2026)

Grants Pass, Oregon, the Josephine County seat — a major southwest Oregon Rogue River Valley community, the gateway to the Wild and Scenic Rogue River (Grants Pass is the primary takeout for Rogue River whitewater trips — the Rogue River Gorge downstream of Grants Pass is a National Wild and Scenic River), home of the famous 'It's the Climate' motto (Grants Pass's mild year-round climate — consistently one of the best climates in Oregon — spawned its famous boosterism motto), a diverse Josephine County community in the Oregon–California border region, and the center of southwest Oregon's emerging wine region and outdoor recreation economy — draws its municipal water supply from the Rogue River via the City of Grants Pass Water Division. Water hardness in Grants Pass measures 65 mg/L — classified as soft.

Grants Pass's soft supply reflects the Rogue River Klamath Mountains watershed's highly calcareous-poor geology. The Rogue River at Grants Pass–Josephine County drains: the Klamath Mountains (Jurassic–Cretaceous calcareous-poor Josephine Ophiolite, peridotite, serpentinite, and Rogue Valley metavolcanic sequence — the highly siliceous and ultramafic Klamath Mountains ophiolite terrane, highly resistant to weathering and generating virtually no calcium carbonate). The Klamath Mountains ultramafic geology produces the soft 65 mg/L.

With hardness at 65 mg/L, Grants Pass residents enjoy soft water. City of Grants Pass Water Division consistently delivers water meeting all Oregon DEQ and EPA Safe Drinking Water Act requirements.