Retaining Walls: Federal Way vs Kent
How do retaining walls rules compare between Federal Way, WA and Kent, WA?
Federal Way and Kent have similar restriction levels.
Federal Way, WA
King County
Retaining walls over 4 feet tall require a building permit and engineering in Federal Way under IBC 1807. Walls with surcharge (driveway, pool) require permits at any height. Geohazard areas add review.
View full Federal Way rules →Kent, WA
King County
Kent requires a building permit for retaining walls over 4 feet tall measured from footing to top. Walls supporting surcharges or on geologically hazardous slopes need a permit at any height under WAC 51-16.
View full Kent rules →Key Facts Comparison
| Fact | Federal Way | Kent |
|---|---|---|
| Permit Trigger | Over 4 feet tall | - |
| With Surcharge | Any height | - |
| Code | IBC 1807 / FWRC 13 | WAC 51-16-080 / KCC 11.06 |
| Engineer Required | WA-licensed PE | - |
| No Permit | - | Under 4 feet unsurcharged |
| Permit Needed | - | Over 4 feet or surcharge |
| Critical Areas | - | Always permit needed |
Highlighted rows indicate differences between cities.
Federal Way FAQ
Do I need a permit for a 3-foot Federal Way retaining wall?
Generally no, unless it supports a surcharge like a driveway or structure. Walls 4 feet or taller always require a permit with engineering.
How do I permit a retaining wall in Federal Way?
Submit stamped engineering plans to Federal Way Permit Center at (253) 835-2607 with soils report if in a geologically hazardous area.
Kent FAQ
Do I need a permit for a retaining wall in Kent?
Only if the wall exceeds 4 feet from footing to top, supports a surcharge, or sits in a critical area under KCC 11.06.
Is a rockery considered a retaining wall in Kent?
Yes. Kent treats dry-stack rockeries under the same 4-foot height threshold as engineered retaining walls.
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