Water Supply

Masonry Pool Reservoir
Masonry Pool Reservoir – This photo was taken on March 29, 2020 by Kevin Johnson.

March 31, 2020

Last week, 4.77 inches and 4.71 inches of precipitation were recorded in our Cedar River and South Fork Tolt River watersheds, respectively. Snowpack is close to the long-term median for this time of the year. 

Chester Morse Lake at the Overflow Dike was at elevation 1555.6 feet, about 0.6 feet higher than last week, and about 2.3 feet above its long-term average (based on the years 1990 to 2019). Masonry Pool Reservoir at Masonry Dam was at elevation 1555.4 feet, about 0.7 feet higher than last week, and about 3.0 feet above its long-term average. The South Fork Tolt Reservoir at the South Fork Tolt Dam was at elevation 1758.8 feet, about 1.0 feet higher than last week, and about 1.2 feet above 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 98 million gallons per day (mgd). That is lower than the 106 mgd consumed during the same period last year, and less than the average of 103 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 this spring.

As always, we continue to ask customers to use water wisely. 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