Retaining wall permit checklist — King County, Washington
Assembled from King County’s own published permit rules. Every line below is quoted from a city document and linked to it. Nothing here is generated, estimated, or inferred from another jurisdiction.
Do you need a permit?
King County requires a permit for a retaining wall.
King County's exempt list covers 'most retaining walls 4 feet high or less' under the Washington State Building Code. The hedged wording ('most') matters: the 4-foot limit is the wall's full structural height, buried footing included, and the exemption is lost whenever the wall holds back anything beyond level soil — sloping ground, a structure or driveway above, or stored hazardous liquids — or sits within a critical area. Retaining walls are the permit type most likely to be captured by King County's critical-areas overlay, because walls tend to be built on the steep slopes, stream buffers and flood-prone ground that trigger it. Any wall requiring cut or fill also triggers separate clearing and grading review.
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Sources
- retaining wall — permit rules ↗verified August 2026
Other permits King County publishes rules for
Listed because the city publishes a separate rule for each type — not because this project necessarily triggers one. Whether it does depends on your scope of work.
- Deck permit checklist
- Fence permit checklist
- Shed permit checklist
- Water heater permit checklist
- Re-roof permit checklist
- Electrical work permit checklist
- General building work permit checklist
BuildSpec is a reference, not the authority having jurisdiction. Confirm requirements with King County before you build.