If you have any questions about the facts and timelines listed below, please contact the Public Works Department at 425-888-0486.
Late 1940s - Early 1950s
The city’s first public water system was constructed in the Clough Creek watershed near Rattlesnake Mountain. The system consisted of a small concrete dam and a 225,000-gallon water reservoir.
As a result of flooding and landslides during the 1964-1965 winter, the city relocated the water system intake 1,600 feet upstream of the existing facilities.
Development of spring on west side of Mt. Si resulting in a 1,500 gallons per minute source pump station, transmission main, and 0.5 MG storage tank at Clough Creek. Clough Creek intake maintained as emergency source only.
Clough Creek facilities abandoned as condition of the Washington State Department of Social and Health Services grant agreement acceptance for water system improvements.
Infiltration gallery built at Mt. Si Spring to protect from surface water intrusion.
2.0 MG reservoir constructed near Interstate 90 Exit 31 to meet increased demands.
Application for additional water rights made to the Washington State Department of Ecology.
A 0.75 MG tank and two-pump station constructed for Forster Woods and Rock Creek Ridge Developments.
During development of the Comprehensive Water Plan, the city found demand for water had exceeded rights for withdrawal at Mt. Si Springs. City voluntarily enters development moratorium.
City explored various sites and different scenarios for obtaining additional water.
Exploratory well drilled at public works site. Hobo Springs suggested as source of mitigation water to lessen impact of drawdown on Snoqualmie River.
September 27, 2007
Washington State Department of Ecology publishes Report of Examination.
April 10, 2008
Washington State Department of Ecology issues city water right permit to appropriate 3,094 acre feet per year at no greater than 2,646 gallons per minute.
Hobo Springs mitigation pipeline, intertie to Sallal Water Association well, and NB-3 production well construction begins.
April 7, 2009
Development moratorium expires.
Hobo Springs mitigation pipeline and NB-3 Centennial well projects accepted as complete.