The Seattle Steam Company

{Pioneer Square}

The two adjoining plants of the Seattle Steam Company are among the last remnants of industrial Pioneer Square. The southern building (known as Old Post) was built around 1890 by the Seattle Heat and Power Company. It used steam to heat nearby buildings and provided pressurized water to run hydraulic elevators.

In 1900 this company merged with the Seattle Electric Company and built a second building (New Post) in 1902. This plant was expanded in 1904 from 8 coal-fired boilers to 11 boilers, to serve all of downtown Seattle. In 1911 the company merged once again, becoming part of Puget Sound Power and Light Company, the conglomerate that owned the city's streetcar system.

In 1951 Seattle City Light purchased Puget Sound Power's (now Puget Sound Energy) portion of the electrical system, and Seattle Steam became a private company. It still provides steam for heating throughout downtown and on First Hill. Much of the steam generation is done at Seattle Steam's larger and more recent plant, located farther north on Western Avenue.

To learn more about this building, visit the City of Seattleā€™s historical sites page.

Listen to a podcast from the Pioneer Square Walking Tour.

Western Avenue and Columbia Street (1mb mp3)

Find this building on our walking tour map. (680kb pdf)

Seattle Steam Company, 1906. Photo courtesy of University of Washington Libraries, Special Collections, Seattle Photograph Collection, Warner 205
Seattle Steam Company, photo courtesy of Seattle Steam Company

About us

This site is dedicated to the history of Seattle's downtown and waterfront, especially the State Route 99 / Alaskan Way Viaduct corridor. It was developed by the Washington State Department of Transportation and the Federal Highway Administration as an educational resource and as part of a Memorandum of Agreement for Section 106 of the National Historic Preservation Act (pdf 1mb).

Copyright 2011 Washington State Department of Transportation