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Transportation Development Tax & Transportation System Development Charges

The Transportation Development Tax (TDT) is imposed on most new development and redevelopment throughout Washington County. The tax makes sure that development helps pay for transportation improvements to accommodate growth caused by the development.

TDT funds can be used to pay for improvements to major roads, such as turn lanes, sidewalks, bike lanes and transit projects (such as bus shelters). The Washington County Coordinating Committee oversees the TDT program.

Transportation System Development Charges (TSDC) also help pay for the cost of transportation improvements resulting from new development in specific areas. TSDCs are in addition to TDT, and the funds may be restricted to projects within or nearby the new development area.

The TDT and TSDCS are collected before building permits are issued. If building permits are not needed, the TDT and TSDCS are collected before final approval of development applications. Payment options include:

  • Payment over time
  • Deferral of payment until occupancy, in certain cases
  • TDT credit may be requested for construction of eligible road or sidewalk improvements




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