Alternate Uses and Benefits of TDRs

Transferring development rights is a way for landowners to realize a financial return from conserving their property and also allows developers to achieve increased density in qualified receiving areas, but there are other potential benefits associated with TDR for sending site landowners.

TDR may reduce your property taxes

When the county certifies development rights from a sending site, the landowner grants a conservation easement on the property. Because conservation easements limit some or all future development and retain a property’s conservation values, easements are one way to achieve property tax reductions through King County's Public Benefit Rating System (PBRS). There are other requirements for enrollment in the PBRS program, but generally speaking, if a property is eligible for the TDR program it will also be eligible for the PBRS program, and vice versa.  Please visit the PBRS website to learn more about reducing your property taxes with TDR.

TDR may satisfy transportation concurrency requirements

New developments or subdivisions in Rural areas (outside the Urban Growth Area) are required to meet transportation concurrency requirements; For each new development or subdivision, there must be adequate transportation infrastructure within a given commuting area – called a “travel shed” – to accommodate increased traffic that comes with additional development. 

Since transferring development rights results in permanently removing development potential from sending sites, which creates a net long-term reduction in traffic, TDRs removed from sending site in the same travel shed may be used to satisfy transportation concurrency requirements (King County Code chapter 14.70.285). TDRs used for traffic concurrency cannot also be used to increase density.

Learn more about the Transportation Concurrency Program on King County Department of Local Services – Road Services Division website. 

Rural TDRs may allow you to build a larger ADU*

King County Code chapter 21A.08.30 establishes regulations for building an Accessory Dwelling Unit (ADU). In the Rural Area zones, ADUs are allowed under certain conditions. In most cases, these ADUs are limited to 1,000 square feet. However, in certain cases a Rural TDR can be used to increase the allowed size of ADUs to 1,500 square feet. It is important to note that each parcel and development proposal will have a unique set of conditions and circumstances; final authority rests with King County Department of Local Services - Permitting Division to approve residential ADU's. Contact King County Permitting Division or a TDR program staff member if you have questions about using TDRs to permit a larger ADU.

* NOTE: On December 10, 2024, the Council adopted the 2024 Comprehensive Plan - see Proposed Ordinance 2023-0440 (Download PDF, see page 228). Substantive amendments to the 2024 Comprehensive plan include revisions to King County Code chapter 21A.08.30.  Building a larger ADU using a Rural TDR will no longer be allowed under the updated King County Code, effective January 2, 2025. Regular rules on vesting apply to ADU projects using TDRs: Once a complete application meeting all requirements is filed, the project is considered vested per King County Code chapter 20.20.070.  If an ADU application is complete prior to January 2, 2025, this update would not affect the project.