Seattle Public Utilities

Current Water Supply Conditions

  • Masonry Pool ReservoirMasonry Pool Reservoir – This photo was taken on August 12, 2018 by Kevin Johnson.

August 14, 2018

Last week, 0.47 inches and 0.33 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 1550.8 feet, about 1.1 feet lower than last week, and about 2.2 feet below its long-term average (based on the years 1985 to 2014).  Masonry Pool Reservoir at Masonry Dam was at elevation 1550.1 feet, about 1.4 feet lower than last week, and about 1.6 feet above its long-term average.  The South Fork Tolt Reservoir at the South Fork Tolt Dam was at elevation 1745.4 feet, about 2.6 feet lower than last week, and about 6.6 feet below its long-term average.  Water releases from reservoir storage are actively being managed for water supply and fish habitat management objectives for both the Cedar and South Fork Tolt Rivers.

Water consumption for the previous seven days averaged approximately 186 million gallons per day (mgd).  That is lower than the 189 mgd consumed during the same period last year, and more than the average of 181 mgd used during the same period over the years 1999-2014.

Based on current conditions and forecasts, Seattle Public Utilities has sufficient supply to meet demands this summer for both people and fish.  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

Related Links

Current water supply graphs (pdf)
Landsburg Mitigation
Water Sources and Treatment