Snowmelt is the big test
Many Spokane homes have basements, and spring snowmelt is when they're tested. NOAA's engineering weather data for Spokane lists a 50-year ground snow load of 42 pounds per square foot; that much snow melting quickly, or rain on frozen ground, sends a lot of water toward foundations. Clean gutters before winter, extend downspouts well away from the house, grade soil away from the foundation, and keep window wells clear and covered.
Sump pumps and frozen lines
Sump pumps are common in Spokane basements. NOAA's data records about 72 freeze-thaw cycles a year, and discharge lines that freeze leave the pump unable to move water just when snowmelt begins. Slope discharge lines to drain, bury or insulate them where possible, and add a freeze-resistant outlet near the house. Test the pump before spring melt and consider a battery backup.
Frost and foundation walls
A joint City of Spokane and Spokane County codes policy sets frost depth at 24 inches for footings. Water trapped against walls and freezing can widen cracks. Seal leaking cracks with injection, and have bowing walls evaluated.
Irrigation and backflow
Homes with irrigation in the City of Spokane must have a backflow assembly tested every year, ideally before the irrigation is turned on. If the assembly sits in a basement or crawlspace, keep it accessible and make sure a leak there won't soak finished areas.
Radon
The EPA recommends testing homes for radon. Test before finishing a basement, and mitigate if levels are high.
Finishing a basement
Confirm the basement stays dry through a full spring melt, insulate walls with rigid foam, plan egress windows for bedrooms, and include heating and a dehumidifier.
Before you hire
Ask Spokane contractors where the water is coming from, how they'll keep discharge lines from freezing, what backup they recommend, and whether permits are needed. Use L&I's contractor lookup to check their Washington registration, bond and insurance.
Older foundations
Many older Spokane homes have block or stone foundation walls that seep more than poured concrete. Interior drainage with a sump pump is often the practical fix.
Dehumidifiers
Basements can be humid in summer when warm air meets cool walls. A dehumidifier with a drain line keeps humidity down and protects finishes and stored items.
Crawlspaces
Homes with crawlspaces need a sealed vapor barrier over the soil, drainage if water collects, and the right venting or conditioning for the design. Check after snowmelt for standing water and wet insulation.
Sealed pit lids
A sealed lid on the sump pit keeps humid air and soil gases, including radon, out of the basement.