Building a Shed in Mukilteo? Here's What You Need to Know

Mukilteo has some of the most unusual shed rules in the area — structures under 120 square feet and 12 feet tall can sit right on the property line with zero setback. But there's a catch: all accessory structures must have a pitched roof (no flat roofs), sidewalls max out at 8 feet, and fabric or tarp structures are flat-out prohibited. Parts of the city also fall under Paine Field airport compatibility zones and Puget Sound shoreline buffers, which can restrict what and where you build.

Building Codes & Permits in Mukilteo

Shed Permit RulesCity of Mukilteo
Max Shed Size (No Permit)200 sq ft (one-story)
Max Sidewall Height8 ft
Setbacks (Small Sheds)0 ft for structures ≤120 sq ft and ≤12 ft*
Setbacks (Side/Rear)5 ft (standard)
Setbacks (Front)Per zoning district — see MMC 17.20

*Zero setback applies to detached buildings 12 ft or less in height and 120 sq ft or smaller. Only one accessory structure may be within 5 ft of the rear and/or side lot line. All accessory structures must have a pitched roof — flat roofs and fabric/tarp structures are not allowed.

From the Municipal Code

Zero setback is allowed for rear and side yard setbacks for detached buildings twelve feet or less in height and one hundred twenty square feet or smaller, provided no more than one accessory structure is within five feet of the rear and/or side lot line.

MMC 17.20 — Zero Setback for Small Accessory Structures

All accessory structures must have a pitched roof.

MMC 17.20 — Pitched Roof Requirement

What You Need to Know

  • Zero setback for small sheds (MMC 17.20): Structures 120 sq ft or smaller and 12 ft or less in height can sit right on the property line — no setback required. Only one accessory structure can be within 5 ft of the lot line.
  • Pitched roof required (MMC 17.20): All accessory structures must have a pitched roof. No flat roofs allowed on sheds in Mukilteo.
  • 8 ft sidewall height (MMC 17.20): Sidewalls on accessory structures max out at 8 ft. Overall height varies by setback distance.
  • Fabric/tarp structures prohibited: Temporary structures made of fabric, tarp, or similar materials are not allowed as accessory structures in Mukilteo.
  • Paine Field compatibility zone: Some properties fall under the Snohomish County Airport (Paine Field) compatibility zone, which can impose additional height restrictions and noise considerations.
  • Shoreline buffers: Properties near the Puget Sound waterfront are subject to a 200 ft shoreline buffer zone. Check if your property is affected before planning a shed location.
  • Setbacks (MMC 17.20): Standard setback is 5 ft from side and rear property lines. The zero-setback exception for small structures is the standout rule here.
  • Outside city limits? Areas around Mukilteo may be unincorporated Snohomish County with different rules. Check the Snohomish County page.
  • Utilities: Even if the structure is exempt, any electrical or plumbing work requires a separate trade permit.

Have questions about permits or zoning? We don't have all the answers, but we deal with this stuff regularly and can usually help you figure it out. Reach out with your address and we'll point you in the right direction.

Building codes and permit requirements are subject to change. Contact your local building department to verify current regulations before beginning your project.

Ready to build in Mukilteo?

Design your custom shed online and get an instant quote. We build on-site — no delivery hassles.