Retaining Walls: Kent vs Redmond
How do retaining walls rules compare between Kent, WA and Redmond, WA?
Kent has fewer restrictions than Redmond.
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 →Redmond, WA
King County
Retaining walls over 4 feet tall (measured from footing bottom to wall top) or supporting a surcharge require a building permit and engineered design in Redmond under IBC and RMC 15.06.
View full Redmond rules →Key Facts Comparison
| Fact | Kent | Redmond |
|---|---|---|
| No Permit | Under 4 feet unsurcharged | - |
| Permit Needed | Over 4 feet or surcharge | - |
| Critical Areas | Always permit needed | - |
| Code | WAC 51-16-080 / KCC 11.06 | RMC 15.06 / IBC |
| Permit Trigger | - | Over 4 ft from footing |
| Engineering | - | WA-licensed engineer |
| Critical Area | - | Extra environmental review |
Highlighted rows indicate differences between cities.
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.
Redmond FAQ
Do I need a permit for a 3-foot landscape wall?
Typically no, as long as it is not supporting a surcharge and is outside a critical area. Decorative stacked block under 3 feet is usually exempt.
What engineer do I need for a tall retaining wall?
A Washington-licensed civil or structural engineer must stamp plans for any wall over 4 feet from footing bottom to top of wall.
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