Water Supply Conditions
The current supply conditions for Seattle's regional water system.
Masonry Pool, September 21, 2025. This photo was taken by Kevin Johnson.
September 22, 2025
Last week, the 7-day precipitation total for the period 9/15/2025 through 9/21/2025 was approximately 0.58 inches in the Cedar River watershed and 0.66 inches in the South Fork (S.F.) Tolt River watershed.
Chester Morse Lake at the Overflow Dike was at an elevation of 1548.6 feet, about 0.7 feet lower than last week and about 1.6 feet lower than its long-term average (based on the years 1990 to 2019). The S.F. Tolt Reservoir at the S.F. Tolt Dam was at an elevation of 1730.6 feet, about 2.5 feet lower than last week and about 10.9 feet lower than 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 S.F. Tolt Rivers.
Water consumption for the previous seven days averaged approximately 146 million gallons per day (mgd). That is more than the 130 mgd consumed during the same period last year, and more than the 133 mgd used during the same period over the years 2010-2019.
Seattle continues to closely monitor conditions and make operational adjustments to efficiently manage the region’s water supply through this dry year. As always, we continue to ask customers to use water wisely. For information about ways to save water, visit www.savingwater.org.