The Green River begins in the Cascade Mountains near Stampede Pass and serves as Tacoma Water’s primary water supply. For more than 90 years, Tacoma Water has managed the Green River watershed. This forested land serves as a collecting point for melting snow and seasonal rainfall. The watershed covers 147,394 acres on the west flank of the Cascade Mountains between Chinook and Snoqualmie passes. Tacoma Water owns only 10 percent of the watershed, but has agreements with other landowners to limit activities in order to keep the Green River water supply pure and fresh.
Our First Diversion water right is for up to 73 million gallons of water daily (MGD) under the First Diversion water right and up to 65 million gallons of water daily under the Second Diversion water right. This water flows by gravity to Tacoma and minimizes expensive pumping costs.
In addition to our First Diversion water right, the Green River is also the source of supply for a regional partnership formed by the City of Kent, the Covington Water District, the Lakehaven Utility District and Tacoma Water. The Regional Water Supply System (RWSS), supplies up to 65 MGD under the Second Diversion water right to Tacoma Water and its project partners. The partners participate in the Second Supply Project under the terms of an agreement in which Tacoma Water has a 15/36 Participant Share and the City of Kent, the Covington Water District and the Lakehaven Utility District each have a 7/36 Participant Share. Generally, a Participant Share represents a participant’s proportional right to receive, and obligation to pay for, water delivered by the RWSS.
We also operate a wellfield along the North Fork of the Green River within the watershed. The North Fork wells are used to meet Tacoma’s needs, only when the water in the river is too turbid (or cloudy), usually in the fall and winter, or in the event of other unusual or unacceptable water quality in the Green River.