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4月
22

Unincorporated King County

King County, Washington

TDRs may be used in certain areas of unincorporated King County.  Unincorporated King County includes parcels regulated by King County zoning which are those not located within an incorporated city.

Basic criteria for receiving sites are outlined below. The TDR Code has the detailed criteria for receiving sites.

Areas qualified to receive TDRs include:

  • Unincorporated King County urban areas zoned R-4 through R-48, NB, CB, RB, or O. In zones R-4 through R-48 there may be opportunities for inclusionary housing bonus (King County Code 21A.48.020 and 21A.48.030) or low-cost TDRs to apply to development projects with certain affordability provisions (KCC 21A.37.130).
  • Rural areas zoned RA-2.5 if TDRs originate in a Rural Forest Focus Area and all of the following conditions are also met:

    • The site is served by a domestic Group A public water service;
    • The site is within ¼ mile of an existing predominant pattern of lot sizes smaller than 5 acres;
    • The project will not adversely impact regionally or locally significant resource or environmentally sensitive areas; and
    • The project will not require public services and facilities to be extended in order to create or encourage a new pattern of smaller lots.
  • • Snoqualmie Pass rural town

The following areas cannot receive TDRs under any circumstances:

  • Properties on Vashon or Maury Islands,
  • Properties within the Rural Forest Focus Area, or
  • Properties within the outer boundaries of the Noise Remedy Area identified by Sea-Tac International Airport.

Using development rights on a receiving site

In qualified urban receiving sites, for developments with nine or fewer units, TDRs may be used to increase density (typically 50%) above what is allowed by the base zoning. For developments with 10 or more units, TDR use may be allowed in accordance with 21A.48.020 or 21A.48.030.  

In eligible rural areas zoned RA-2.5, TDRs originating from Rural Forest Focus Area may be used to achieve maximum density of one dwelling unit per 2.5 acres.

TDRs may also be used to build duplexes in eligible small lots in Snoqualmie Pass Rural Town in accordance with 21A.08.030.B.12.     

When you apply to King County for a residential building permit or apply to subdivide land, you will need to supply proof that you have access to the development rights required for the project. The proof could be a letter of intent in your name or a signed and notarized option to purchase development rights from someone who owns a certificate, or a TDR certificate issued in your name. Proof of availability of TDRs for the project is sufficient to start the King County review process on your development application.  (See additional information about permits from King County Permitting Division).

Before receiving a building permit or final plat or short plat recording, you will need to deliver to King County Permitting Division a TDR certificate in your name for the number of transferrable development rights you wish to apply at the site.

Following permit issuance, you will need a TDR extinguishment document that shows the TDRs have been used and cannot be used again on another project.

For TDR transactions within unincorporated King County, each Rural TDR allows two additional units in urban receiving areas; each Urban TDR allows one additional unit. 

To learn more:

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