Des Moines ground, weather, and permits
The city’s critical areas code regulates ravine sidewalls and bluffs, landslide and erosion hazard areas, and any hillside of 15 percent or more. Slides are part of the local record. A January 2006 slide closed a lane of Des Moines Memorial Drive on the 23rd straight day of rain, and in March 2015 a slide near Saltwater State Park left three homes unsafe to occupy. On the plateau above the slope, expect the dense glacial till typical of the Puget Lowland, where rain tends to stay near the surface. We probe each lot instead of assuming.
Planning, Building and Public Works handles building, grading, and critical areas permits. Work in the street right-of-way goes through the Public Works Permit Center under chapter 12.05 of the city code. Stormwater follows the King County Surface Water Design Manual, and the city’s current standard is the 2026 edition, in effect since July 1, 2026. Before quoting, we read the mapping and permit rules for your parcel.
Nearby, we also build in Federal Way, Normandy Park, Burien, and Kent, and we serve the rest of Pierce and South King County.