Concrete Retaining Walls in East Renton Highlands, WA

Retaining walls in East Renton Highlands: what to know

The county exempts a wall not over 4 feet, measured from the bottom of the footing to the top, unless it supports a surcharge such as a driveway or a building. King County’s permit page adds that the exemption holds only if the property has no critical areas.

Grade changes show up at a driveway cut, along a back yard, or where ground falls toward a creek or the river valley. A steep slope hazard area is steeper than 40 percent with at least 10 feet of rise, with a 50-foot minimum buffer without a report. Cutting over 5 feet deep or filling over 3 feet deep also calls for a grading permit.

Permits and rules in East Renton Highlands

The Department of Local Services, Permitting Division, issues building and grading permits for unincorporated King County. A wall that carries a surcharge, or stands over 4 feet from the bottom of the footing, needs a building permit. Within 65 feet of a potential steep slope with more than 10 feet of rise, the county generally asks for a report from a geotechnical engineer or geologist authorized in Washington. Before we price a wall, we look up your parcel’s slope, landslide, and erosion layers.

Rules change and vary by parcel, so we confirm the current requirements with the city before we start.

How we approach it

Add footing depth to the visible face before judging 4 feet
Pull the slope, landslide, and erosion layers before staking the footing
Bring in a geotechnical engineer for walls near a mapped slope
Send wall drainage to the natural discharge point, never onto a neighbor

For the full process, see our Retaining Walls page.

Building in the cold months? See our guide to winter concrete pours.

Our retaining walls work, serving East Renton Highlands

Examples of our work. We build retaining walls in East Renton Highlands and the cities around it. See all of our work

Questions from East Renton Highlands homeowners

Does a 4 foot retaining wall in East Renton Highlands need a King County permit?

Not if it is no more than 4 feet from the bottom of the footing to the top, carries no surcharge, and the property has no critical areas. A driveway or building above the wall removes the exemption.

How steep must a slope be before King County treats it as a hazard near my wall?

A steep slope hazard area is steeper than 40 percent with at least 10 feet of vertical rise. The minimum buffer without a report is 50 feet, and a report is generally required within 65 feet of one. The county’s map layers show where to look.

Where should the drain behind a retaining wall here discharge?

At the natural discharge location. The county’s stormwater manual bars diverting runoff onto or away from downstream properties and requires that it not harm lots downhill. Near a landslide or steep slope area it asks for more. We settle the outlet before we pour.