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Significant historic and archaeological properties including buildings, sites, districts, objects, and structures in unincorporated King County are protected by certain design review processes and may be eligible for certain incentives.

Certificates of Appropriateness (COA) through Historic Preservation Program

Any major restoration or changes of a significant feature of a designated King County Landmark property in unincorporated King County requires a Certificate of Appropriateness (COA), which is granted through a design review process. "Landmark" refers to a physical property that has been formally designated and listed on a register of historic places by an agency of government.

The COA process is separate from the building permit process. COAs must be obtained through the King County Historic Preservation Program before building permits are issued. Some projects that do not require building permits may still require COAs.

It is best to initiate the design review process prior to applying for any required permits from the Permitting Department. If you submit an application for a building or development permit to the Permitting Department without seeking a needed COA, the Permitting Department will refer the project back to the Landmarks Commission for its review and approval.

More importantly, design review may result in changes to the project specifications; the Historic Preservation Program recommends applying for a COA prior to finalizing your plans.

Please refer to: