King County Retaining Wall Contractor

Reviewed by the Seattle Rockeries project team. Updated 2026. Based on more than two decades of retaining wall, rockery, drainage, and hardscape construction in Pacific Northwest conditions.

Seattle Rockeries builds retaining walls, rockeries, block walls, and drainage systems across King County. We are licensed, bonded, and insured in Washington, and we have spent more than two decades on the one problem that makes local walls fail: water on slopes with tight access.

Why King County Walls Are Their Own Problem

A retaining wall in King County is rarely just a wall. The county runs from old Seattle city lots with narrow side yards to Eastside hillsides, plateau backyards, and waterfront slopes, and almost all of it sheds water through a long wet season into clay-heavy and glacial soils.

That means the same wall costs and behaves differently depending on where it sits. A low landscape wall on an open Redmond lot is a straightforward job. A failing timber wall behind a Seattle home you can only reach down a side yard, or an engineered wall holding a waterfront slope on Mercer Island, is a different project with different access, drainage, and design demands. We build for the conditions in front of us, not a one-size template.

Permits Change With the Jurisdiction

King County has both incorporated cities and unincorporated areas, and the permit rules are not the same across them. Seattle answers to SDCI. Bellevue, Kirkland, Issaquah, and the other cities each set their own thresholds. Unincorporated King County follows county code. Height, surcharge loads, critical areas, and drainage connections can all trigger review.

We help flag the likely permitting questions for your site, but the final call comes from the jurisdiction or a qualified design professional. The cost guide permit section lays out the Seattle, Bellevue, and unincorporated King County rules in detail, with links to the official sources.

Where We Work Across King County

We work throughout King County, and each area brings its own terrain, access, drainage, and permitting considerations. These are the areas we serve, each with its own terrain and permit realities:

• Bellevue — Eastside hillside lots and high-end hardscape. Block walls and driveway support are common, and Bellevue permits kick in over 4 feet or with any surcharge, plus the Critical Areas Overlay and a setback rule for walls over 30 inches.
• Mercer Island — Island waterfront slopes, premium properties, tight access, and often engineered walls. This is one of our strongest markets.
• Kirkland — Lake Washington view slopes, hillside terracing, and waterfront-adjacent drainage.
• Issaquah — Steep slopes off the Issaquah Alps, wet soils, and critical areas. Rockeries and slope stabilization are the norm here.
• Sammamish — Plateau backyards, newer homes, and drainage-driven projects.
• Redmond — Sloped backyards, newer developments, and outdoor-living upgrades.
• Renton — Renton Highlands hillside lots, erosion, and failing-wall replacement.
• Newcastle — Hillside lots and views between Bellevue and Renton, with slope-stabilization work.
• Seattle — Older timber walls, narrow city lots, SDCI and environmentally critical area rules, tight access, and drainage.

The Points. We also work the waterfront communities of Medina, Clyde Hill, Yarrow Point, and Hunts Point, where rockery, retaining, and slope work on high-value lots is constant and access is everything. They are minutes from our base.

Beyond these, we serve Bothell, Kenmore, Woodinville, Lake Forest Park, Shoreline, Snoqualmie, North Bend, and surrounding King County communities. If your city is not listed, ask, we may still cover it.

What We Build

• Natural rockery retaining walls using basalt, granite, and limestone boulders, hand-placed for drainage and stability.
• Concrete block retaining walls for engineered, consistent systems and clean hardscape lines.
• Drainage and water management, the part most failures trace back to, built into the wall rather than added as an afterthought.
• Slope stabilization, failing-wall removal and replacement, steps, and pavers.

You can see recent work in our project gallery.

Why Homeowners Across the County Choose Seattle Rockeries

We are licensed, bonded, and insured in Washington, founded and run by Harry Sidhu with a deep family trade background. We look at the site first, recommend the material that actually fits it, and walk you through the tradeoffs, the budget range, and the permitting questions before anyone starts digging.

The walls that fail around here almost always fail for the same reason: water that was never managed on a slope that was never properly drained. That is the problem we build around, on every job, in every part of the county.

Seattle Rockeries serves homeowners across King County, including Seattle, Bellevue, Mercer Island, Kirkland, Redmond, Renton, Issaquah, Sammamish, Snoqualmie, Newcastle, and surrounding communities.