Auburn ground, weather, and permits
The valley floor is river alluvium, built up in part by the Osceola Mudflow from Mount Rainier about 5,600 years ago. The city calls that soil prone to liquefaction in an earthquake. Borings near Auburn for a King County facility found groundwater roughly 3 to 15 feet down, swinging up to 10 feet with the seasons. The uplands around the valley are generally capped with glacial till, and the city lists landslides on the steep hillsides, ravines, and plateaus that border the valley. River flooding concentrates in low areas along the Green and White Rivers.
Community Development issues Auburn’s building permits, mostly through MyBuildingPermit.com, and work in the public way takes a separate construction permit from the city engineer. The Lakeland Hills part of the city lies in Pierce County, and city rules apply there too, while septic approvals come from whichever county health department covers the parcel. Whether a property is inside city limits is the first question, and the city’s permit page links an address lookup for it. Floodplain, shoreline, and critical area rules add review in mapped areas.
Nearby, we also build in Kent, Federal Way, Covington, Lake Tapps, and Bonney Lake, and we serve the rest of Pierce and South King County.