Customer Notice

For the latest information, resources, and guidance related to COVID-19, please visit our COVID-19 information page or visit our COVID-19 Utility Bill Assistance page.

Washington State Area Codes and Numbering Issues

Washington State Number Plan Area (NPA) Exhaust Projections

Washington area code exhaust projections by the Federal Communications Commission (FCC) Numbering Plan Administrator







206      2029 ​2027
253      2040 ​2046
360        2019*   ​2018*
425      2037 2040​
509      2024 ​2025

Area code exhaust projections are calculated by the FCC's North American Numbering Plan Administrator (NANPA). Communication service providers submit anticipated number resource use twice a year to the FCC.  Those projections are calculated and then dates released by the FCC on when an area code will run out of numbers.

Numbering Efficiency and Conservation in Washington State

Inefficient allocation of prefixes without number pooling has been the main cause of area code exhaust nationwide.  The UTC and federal regulators require service providers to use the existing supply of numbers efficiently through the following:  

  • Rate center consolidations help conserve numbering resources by expanding the area in which a prefix may be used.
  • Number pooling conserves numbers by allowing up to ten companies to share a single telephone prefix (which has a total of 10,000 numbers available).
  • State and federal regulatory number resource compliance oversight.

Number Portability

Number portability allows a customer to keep her telephone number when there is a change of service provider, location or service. The FCC (Order CC Docket 99-200) requires all service providers to port numbers.

  • Customers should direct number portability questions to their current company.
  • If you have problems with number porting after contacting your current company, you may contact the UTC Consumer Protection Help Line.
  • Companies may direct number portability inquiries to UTC Regulatory Service Telecom Staff.

Area Code Changes

 Western Washington:

  • The UTC approved a plan to overlay a new area code (564) over the current 206, 253, 360, and 425 area codes.
  • The new area code overlay requires customers to dial ten digits to complete a local call throughout western Washington.
  • In May of 2016, the Commission ordered a number exhaust relief plan in Docket UT-143787 to be completed by the end of 2017.

Eastern Washington:

  • In 2002, a plan to overlay the 509 area code with a second code (and require ten digit local dialing) in Eastern Washington was proposed by FCC representatives on behalf of communications service providers; however, the UTC dismissed the proposal and instead directed that efforts be focused on using the existing limited supply of number resources more efficiently.

  • The UTC also directed its staff to identify unused prefixes, monitor projected demand, research and implement conservation efficiencies, and require service providers to share prefixes in compliance with federal and state rules.
  • As a result of these activities the forecasted life of the 509 area code has been extended (see table at the top of this page).



* The original projection in 2015 was for 3Q 2017 and later updated to 1Q 2019; but now, as of March 25, 2016, the revised projection for area code (360) is 1Q 2018 via the NANP Administrator's Delta NRUF. The full 2016 exhaust projection report (which was most recently published in April 2016) confirms the Delta NRUF.