Salmon Creek Water Hardness & Quality Report (2026)

Clark Public Utilities (CPU) serves Salmon Creek, WA, supplying water to Clark County including areas near Salmon Creek and Vancouver. The utility draws from multiple groundwater aquifers — the Recent Alluvial Aquifer, Troutdale Aquifer, deep Sand and Gravel Aquifer, and fractured basalt formations — via wells throughout unincorporated Clark County. There are no named surface water treatment plants; water is extracted from wells, treated for disinfection and other processes, and distributed to residential, commercial, and industrial customers. The service area includes communities along Salmon Creek and the East Fork Lewis River within the Lower Columbia watershed (HUC 17090012), near USGS monitoring site 14213000 with a drainage area of 80.7 sq mi.

The supply lies within the Lower Columbia River watershed, where groundwater percolates through Quaternary alluvial sediments deposited by glacial and fluvial activity, the Tertiary Troutdale Formation's sands and gravels, and Miocene Columbia River Basalt Group fractured volcanics. This multi-aquifer system allows deep circulation through basaltic minerals and limestone-influenced alluvium, dissolving calcium and magnesium ions during recharge. The fractured basalt enhances prolonged mineral contact, producing a moderately mineralised supply without surface runoff dilution.

At moderately hard levels, scale buildup accumulates on fixtures and in water heaters, dishwashers, washing machines, and faucets, where deposits can reduce water heater efficiency by up to 20–30% and shorten appliance life. Regular vinegar descaling, installing sediment filters, and flushing water heaters biannually help manage buildup. A water softener is recommended to prevent spotting on dishes and glassware and reduce soap scum, potentially extending appliance life by around 30%. CPU's water meets all EPA MCLGs, with 196+ contaminants within safe levels; tap water is safe per health guidelines.