Water Supply

Masonry Pool Reservoir
Chester Morse Lake Reservoir – This photo was taken on August 11, 2019 by Kevin Johnson.

August 13, 2019

Last week, 1.04 inches and 1.03 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 1550.6 feet, about 0.2 feet lower than last week, and about 2.5 feet below its long-term average (based on the years 1985 to 2014). Masonry Pool Reservoir at Masonry Dam was at elevation 1539.9 feet, about 9.1 feet lower than last week, and about 8.9 feet below its long-term average. The South Fork Tolt Reservoir at the South Fork Tolt Dam was at elevation 1740.0 feet, about 1.6 feet lower than last week, and about 12.3 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 162 million gallons per day (mgd). That is lower than the 188 mgd consumed during the same period last year, and less than the average of 182 mgd used during the same period over the years 1999-2014.

Based on current conditions and forecasts, Seattle anticipates the regional water system will have sufficient water supply for people and fish this summer and 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