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A residential building permit is required in unincorporated King County to construct a new residential building structure or for certain improvements to assure the development is consistent with building codes and other applicable regulations. Per legal authority of Title 16 of the King County Code.

What activities require this permit?

  • A new residence, mobile home, or accessory dwelling unit
  • Any accessory structures such as garages and storage structures (detached storage building less than 200 square feet in area are exempt)
  • Improvements and additions to existing residences or accessory structures
  • Decks over 30" above grade; retaining walls over 4' height; and fences over 6' in height
  • Heating and air-conditioning systems, fireplaces, woodstoves and other heating devices or ventilation systems
  • Relocation or demolition of a structure
  • Changing the use of a home to a daycare, adult family home or a home occupation.
  • A basic residential permit also is available for builders who have a previously approved registered plan and intend to construct the same house on one or more building sites, see Residential Basics Program.
  • Please see related permits administered by other agencies that typically are required with a residential building permit.

Refer to the current fee schedule for a cost estimate.

Where can I get an application?

How do I submit my application?

See Applying for a permit at the Permitting Department and Drop-offs: Permits accepted by drop-off or mail.  Note that some permits can be issued over the counter. Call us at 206-296-6600.

What is the timeline for processing a residential building permit?

Varies depending on permit decision type (refer to Title 20 of the King County Code).

For more information: