Concrete Retaining Walls in Olympia, WA

Retaining walls in Olympia: what to know

The residential list exempts a retaining wall not over four feet from the footing base to the wall crest, unless it supports a surcharge or holds back Class I, II, or IIIA liquids. A taller wall, or a shorter wall with a load behind it, moves to the permit track. We measure the footing and the top at each run, then mark every load on the site plan, including a driveway, a building, or a slope above the wall.

OMC 18.32.610 defines a landslide hazard area by height and slope: at least 10 feet of vertical change, with a slope of 40 percent or steeper, or 15 percent or steeper where water-resistant layers and seasonal seepage are present. Under OMC 18.32.630 the buffer is the larger of 50 feet or one-third of the slope height at the top edge, unless a geologist or geotechnical engineer recommends otherwise, so we ask the city whether a wall sits inside that buffer before the design is drawn.

Permits and rules in Olympia

Before a wall is drawn, we measure each run from footing to top and mark any surcharge, including vehicles, buildings, and slopes above the wall. We check the grade against the 40 percent and 15 percent lines in OMC 18.32.610, and we confirm the buffer answer with the city when the slope qualifies. We look up the stormwater outlet rule under OMC 13.16.020 before any drain is placed at the wall.

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

How we approach it

Measure footing to top on every run before the layout
Mark each surcharge and its distance from the wall face
Check the slope against the landslide hazard line in OMC 18.32
Place the drain outlet clear of streets, lot lines, and inlets

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 Olympia

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

Questions from Olympia homeowners

Which Olympia wall heights pass without a permit?

The residential list exempts a wall not over four feet tall, measured from the footing base to the wall crest, provided no surcharge sits behind it and it holds back none of the Class I, II, or IIIA liquids. Taller walls and loaded walls go through the permit track.

Does a steep slope change an Olympia wall review?

It can. OMC 18.32.610 reaches slopes of 40 percent or steeper with at least 10 feet of vertical change, and slopes of 15 percent or steeper where water-resistant layers and seepage are present. Those slopes carry a buffer under OMC 18.32.630, so we check the grade before the wall is drawn.

Where does drain water from an Olympia wall go?

Water sent to the city storm system needs an engineering permit under OMC 13.16.020 before it is discharged. We compare each outlet against the lot lines, any sidewalk, and any inlet, and we write the chosen point on the wall section.