Transportation Development Tax
The Transportation Development Tax (TDT) is a countywide tax applied to all new developments to help pay for the transportation infrastructure needed throughout the County to accommodate growth. Ultimately, the TDT is designed to generate enough revenue to construct approximately 28% of the growth-related transportation infrastructure called for in the county and cities’ 20-year Transportation Plans.
The TDT is not a property tax. New development is required to pay the tax when a building permit or occupancy permit is issued. The TDT tax rate is uniform throughout the County, and the amount of tax due is based on the estimated traffic generated by each development. TDT taxes are assessed and collected by the Washington County Current Planning Division in unincorporated Washington County, and by the cities within city limits. Remodeling, temporary uses, and state and federal government buildings are exempt from the TDT.
The TDT is not a property tax. New development is required to pay the tax when a building permit or occupancy permit is issued. The TDT tax rate is uniform throughout the County, and the amount of tax due is based on the estimated traffic generated by each development. TDT taxes are assessed and collected by the Washington County Current Planning Division in unincorporated Washington County, and by the cities within city limits. Remodeling, temporary uses, and state and federal government buildings are exempt from the TDT.
All TDT revenue will be dedicated to funding transportation improvements designed to accommodate growth, such as:
- Improvements to Arterial and Collector roadways, including sidewalks and bike lanes;
- Transit capital projects (such as bus shelters).
Developers may be eligible to receive credits against their TDT tax for the value of certain developer-constructed improvements built as conditions of development approval. To be eligible for TDT credits, the improvements must be to an arterial or collector roadway or on the adopted Project List (link to list/map). There are a number of additional limitations on TDT credit eligibility, and developers are strongly advised to consult with appropriate city or county staff regarding credit eligibility prior to investing in an improvement.
Contact the Washington County Current Planning Division at 503-846-8761 for information regarding TDT assessment and collection for unincorporated Washington County. Contact the appropriate city for information regarding TDT assessments and collections within city limits.
