Water Supply

Chester Morse Lake Reservoir
Chester Morse Lake Reservoir – This photo was taken on October 13, 2019 by Kevin Johnson.

October 15, 2019

Last week, 1.74 inches and 1.65 inches of precipitation were recorded in our Cedar River and South Fork Tolt River watersheds, respectively.

Chester Morse Lake at the Overflow Dike was at elevation 1549.3 feet, about 0.3 feet lower than last week, and about 1.8 feet above its long-term average (based on the years 1990 to 2019). Masonry Pool Reservoir at Masonry Dam was at elevation 1519.2 feet, about 0.4 feet higher than last week, and about 11.3 feet below its long-term average. The South Fork Tolt Reservoir at the South Fork Tolt Dam was at elevation 1733.4 feet, about 0.3 feet higher than last week, and about 5.6 feet below its long-term average. Water releases from reservoir storage are actively being managed for water supply, fish habitat and flood management objectives for both the Cedar and South Fork Tolt Rivers.

Water consumption for the previous seven days averaged approximately 109 million gallons per day (mgd). That is the same as the 109 mgd consumed during the same period last year, and less than the average of 112 mgd used during the same period over the years 2010-2019.

Based on current conditions and forecasts, Seattle anticipates the regional water system will have sufficient water supply for people and fish into the fall. As always, SPU will continue to carefully monitor conditions daily and anticipate the return of the fall rains.

Using water wisely is something SPU always asks its customers to do.  For information about ways to save water, visit www.savingwater.org.


Current Water Supply Graphs (pdf)
Area Served by Seattle Regional System (Map) (pdf)
Landsburg Mitigation
Water Sources and Treatment