Commercial Building Permits

Commercial Building permits are needed for the following buildings and structures:

  • Commercial Buildings (new and additions)
  • Multifamily Housing Units (Apartment Buildings, Condominiums, and Townhomes)
  • Tenant Improvements
  • Antennas
  • Personal Wireless Telecom Facilities
  • Signs and Billboards
  • Retaining Walls

Permits may be required for mechanical, plumbing, and fire systems in commercial buildings.  These include:

  • Plumbing (fixtures, water heaters, drains)
  • Mechanical (appliances, ventilations, heating/cooling systems)
  • Fire Alarms Systems
  • Fire Sprinkler Systems
  • Fire Pumps
  • Underground Supply Main (Fire)
  • Gates or Barricades across fire apparatus access road
  • Marijuana Extraction Systems

To apply for any of these permits, go to For more information on how to apply online, see the information on the following page: Online Permitting | Snohomish County, WA - Official Website (


Wildland-Urban Interface Code: Beginning on March 15, 2024, Washington's State legislature implements the 2021 building codes, including standards for buildings in the Wildland-Urban Interface (WUI) area. The code standards, linked below, should be reviewed prior to the implementation of any design or construction project in WUI-designated areas. Find additional details at our WUI page. Several checklists will be affected and new checklists linked to below are in development. View the updated checklists here Version OptionsLand Use ApplicationsHeadline.

A new submittal checklist is being adopted for townhouse and multifamily building permit applications that have a previously approved site plan. The checklist will become effective on March 1, 2024. More information here.

building under construction