Concrete Retaining Walls in Tacoma, WA

Retaining walls in Tacoma: what to know

Tacoma’s slopes have a record. The 1949 slide above the Narrows came three days after an earthquake, and USGS modeling points to high groundwater as a contributing factor. The 2001 earthquake sent a hillside down above Salmon Beach. County hazard planners note that deep slides can begin on slopes as gentle as 15 percent, and that shallow bluff failures often follow clearing vegetation for a view.

So a wall here is designed with the hillside, not as a freestanding box. Footing, reinforcement, and a working drain matter, but so does the load the wall puts on the slope above it. A shorter second tier often does more good than one tall wall.

Permits and rules in Tacoma

Tacoma exempts a wall of four feet or less, footing to top, when nothing loads it, and the city’s FAQ asks for flat ground above and below. A driveway, a building, or a fence counts as a load. Taller walls go through a residential alteration permit with engineered plans. Walls in mapped steep-slope areas also meet the critical areas chapter, and cutting over 50 cubic yards brings site development review. Before we quote, we check your parcel’s mapping and the wall’s load.

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

How we approach it

Read the slope above and below the wall before choosing a height
Check the critical areas map and whether a geotechnical report is needed
Split large grade changes into tiers when that eases load on the slope
Run the wall drain to a legal outlet, never the sanitary sewer

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 Tacoma

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

Questions from Tacoma homeowners

Is a four-foot retaining wall in Tacoma exempt from a permit?

Only if it is four feet or less from footing to top, carries no driveway, building, or fence, and sits on private land. Tacoma’s FAQ also asks for flat ground above and below, so a short wall on a slope may still need review.

Can I build a retaining wall next to the sidewalk in front of my Tacoma house?

City code lets a residential wall up to four feet sit in the right-of-way without a separate occupancy permit if it follows the Public Works Design Manual on sidewalk setback and sight distance. Taller or noncompliant walls are reviewed with the building permit.

Do I need a geotechnical report for a wall on a Tacoma bluff lot?

Possibly. Steep slopes are a regulated geologic hazard here, and projects in them follow a geotechnical expert’s recommendations. The city’s map is advisory, and unmapped lots can still need a site investigation. We check before we design.