Renton sits at a convergence of pest pressure that few other South King County cities experience at the same intensity. The Cedar River corridor feeds Norway rat populations outward into residential streets year round. A Douglas fir tree canopy covering Renton Hill, Kennydale, and the Highlands puts mature rotting stumps the primary nesting habitat for carpenter ants within foraging distance of nearly every home in those neighborhoods. Hundreds of pre 1970 homes throughout Renton Highlands, Renton Hill, and South Renton have settling concrete foundations, wood frame crawlspaces with deteriorated vent screens, and decades of accumulated bark mulch pressed against the structure conditions that make ant and rodent infestations almost inevitable without active prevention.