Seattle and the King County communities around it — each with its own flavor of water trouble.
The core of the coverage area and the hardest on foundations. The older neighborhoods — Ballard, Wallingford, West Seattle, Beacon Hill, Magnolia — combine pre-1980 homes, original clay-tile footing drains, mature trees with invasive roots, and steep lots that funnel water downhill. The low, near-sea-level flats add a high water table on top. If a classic Seattle drainage failure exists, it lives here: a fifty-year-dry basement that starts leaking when its clay tile finally clogs.
Bellevue, Kirkland, Redmond, Sammamish, Issaquah — wealthier, newer in parts, but no drier. The plateau and hillside lots shed water fast, and the wetter pockets sit on the same slow-draining glacial till. Newer construction has modern footing drains, but construction-era shortcuts and the region's slopes still produce wet crawl spaces and soggy yards. Curtain drains earn their keep on these hillside properties.
Shoreline, Lake Forest Park, Kenmore — a mix of mid-century homes near the lake and newer builds up the slopes. Lakeside and low-lying properties see high-water-table basements; the hillside homes above them get the runoff. Downspout and surface drainage solve a large share of the calls here.
Renton, Tukwila, Kent, and the river valleys — flatter ground, closer to the water table, and in the valley floors genuinely low. Flat lots mean less gravity to work with, so sump-based systems are more often the answer than downhill daylight drains.