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Transportation Development Tax to increase July 1, 2024

The Transportation Development Tax (TDT) is imposed on new development to pay for transportation needs created by development. Annual TDT rate increases are based on a five-year rolling composite construction cost index and are capped at 10% annually.
Media release

The Washington County Transportation Development Tax (TDT) rates will increase by 8.29%, effective July 1.

Once the increase takes effect, the TDT rate for a single-family detached home, for example, will be $11,478 – $879 more than the 2023-24 rate of $10,599.

TDT is based on the average estimated traffic generated by the type of new development and is paid by developers to fund transportation projects including road improvements, sidewalks, bike lanes and transit upgrades such as bus shelters. TDT rates are adjusted annually based on a five-year rolling average of road construction, labor and right-of-way costs.

The Board of Commissioners approved the rates increase on April 16. County code calls for the Board to act on TDT adjustments annually before May 1.

Visit Transportation Development Tax and Transportation System Development Charges or view the Transportation Development Tax Rate Schedule for more information.


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