File:Alder Street sewer outfall into Lake Washington, June 19, 1917 (MOHAI 9890).jpg

Prior to 1890, Seattle relied on a haphazard assortment of sewers and cesspools that, at best, drained into surrounding lakes and salt water. Faced with recurring threats of waterborne diseases including typhoid and cholera, City Engineer Benezette Williams designed the Seattle's first centralized combined sewage system plan in 1891. This plan sought to remove as much city sewage as possible into the salt water of Elliott Bay and the Puget Sound with more limited drainage into the fresh water of Lake Washington. Although originally untreated, the City undertook a succession of steps starting in the late 1910's to remove solids, begin primary sewage treatment, and eventually separate storm water from raw sewage. Metropolitan King County took over the City's wastewater treatment responsibilities in the 1960's, but Seattle continues to manage its network of storm sewers. In this image one of the Seattle Engineering Department sewer outfall pipes is seen entering Lake Washington at Alder Street.

Sign in image: Ferry "Issaquah" to Mercer Island; Machine Shop Caption by: http://www.seattle.gov/cityarchives/exhibits-and-education/online-exhibits/a-city-at-work/water-system

• Subjects (LCTGM): Sewerage--Washington (State)--Seattle