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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 our Bulletin #12A, 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: