Concrete Retaining Walls in Snohomish, WA

Retaining walls in Snohomish: what to know

Snohomish’s Title 14 code sets the permit type for each wall. A wall of four feet or less takes a Type 1 permit only when it does not need structural calculations or a drainage system. A series of such walls moves to Type 2 when the slope, run from the base of the lowest wall to the crest of the highest, is greater than 1.5 feet horizontal to 1.0 foot vertical.

The Planning Director can require calculations or a geotechnical report for any wall, prepared by a professional engineer entitled to practice in Washington. Height is measured from the lowest part of the footing to the highest part at every location. Except where the code provides otherwise, a private wall may not sit in city right-of-way or extend into a neighboring lot, and guardrails at the top count neither as a fence nor as wall height.

Permits and rules in Snohomish

We measure each wall from the lowest footing point to the top at every location, then pick the permit type. We confirm whether the wall needs calculations or a drainage system, since that answer decides Type 1 eligibility. The site plan must show the land within 50 feet of the wall, including neighboring parcels, and every structure within that distance, so we check the survey before drafting. The city checklist also asks for a drawn-to-scale site plan, wall design drawings, and the drainage system behind 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 from the lowest footing point to the top at every location
Decide whether the wall needs calculations or a drainage system
Choose Type 1 or Type 2 before the wall design is drawn
Keep the wall off the right-of-way and off the neighbor’s lot

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 Snohomish

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

Questions from Snohomish homeowners

Can a Snohomish wall of four feet or less skip the city permit?

No. SMC 14.110.070 requires a retaining wall permit for every retaining wall. A wall of four feet or less takes a Type 1 permit only when it needs neither calculations nor a drainage system, and the state’s building-permit exemption does not remove the city requirement.

Does a stepped series of Snohomish walls change the permit type?

It can. A series of walls four feet or less moves to Type 2 when the slope from the base of the lowest wall to the top of the highest exceeds 1.5 feet horizontal to 1.0 foot vertical. We measure that slope on the survey before the permit type is set.

Where should a Snohomish wall drain discharge?

The code requires a drainage system behind a Type 2 wall, and a wall that needs one cannot take the Type 1 path. We place the outlet on your own lot, clear of the neighboring lot line, before footing work begins.