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

Arlington allows sheds up to 200 square feet and 9-foot sidewalls without a permit — and unlike most cities, the code explicitly allows storage lofts (up to a third of the footprint). No heating systems in exempt structures, and eave overhangs max out at 2 feet. We're based here, so we know these rules cold. Just outside city limits? Snohomish County rules apply — and they're more generous.

Building Codes & Permits in Arlington

Shed Permit RulesCity of Arlington
Max Shed Size (No Permit)200 sq ft
Max Shed Wall Height9 ft (sidewalls, measured from grade)
Max Shed Eave Height10 ft (per IRC — see below for overall height)
Setbacks (Side/Rear)5 ft* (IRC default)
Setbacks (Front)Varies by zone — see Ch. 20.48

*Arlington's dimensional regulations are in a PDF we couldn't parse for specific setback numbers. IRC defaults are 5 ft side/rear — Arlington likely adopts similar but check with the building department before building.

Overall height is not specifically defined in the IRC for accessory structures. The code limits eave height to 10 ft and story height to 11 ft 7 in for wood framing. Ridge height is a function of roof pitch and building width. However, eave overhangs are limited to 2 ft max projection, and cannot encroach within 3 ft of an adjacent structure or property line (fire separation distance). These setback and fire separation calculations may effectively limit your overall building height.

From the Municipal Code

One-story detached accessory structures not used for human habitation (tool sheds, playhouses, similar uses) are exempt provided floor area within the outside perimeter of the exterior walls does not exceed 200 square feet (18.6 m2) and the sidewalls do not exceed nine feet in height measured from grade average.

SCC 30.50.103(1)(a)(i)(A) — Permit Exemption (Snohomish County, adopted by Arlington)

Eaves may extend a maximum of 24 inches past exterior walls unless encroaching into setbacks. Storage lofts allowed if area doesn't exceed one-third of building footprint; clear height not exceeding five feet for loft areas greater than 70 square feet. Plumbing permits required; heating systems prohibited in exempt accessory structures.

SCC 30.50.103(1)(a)(i)(B–D) — Additional Exemption Rules

What You Need to Know

  • Setbacks (Ch. 20.48): Setback requirements apply even for permit-exempt sheds. Distances vary by zoning district — check the city's accessory shed rules and dimensional regulations for your zone.
  • Easements: You cannot build on a recorded easement (utility, drainage, etc.) regardless of whether you need a permit or not.
  • Outside city limits? Parts of the Arlington area are unincorporated Snohomish County with different rules — up to 400 sq ft in rural areas. If you're outside city limits, check the Snohomish County page.
  • Utilities: Even if the structure itself is exempt, any electrical or plumbing work requires a separate trade permit.
  • Lot coverage: Residential zones in Arlington have a 35% maximum lot coverage per Table 20.48-1. Your shed counts toward this total.

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.

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