Water Supply Conditions
The current supply conditions for Seattle's regional water system.
Chester Morse Lake, September 1, 2025. This photo was taken by Hayley Buzulencia.
September 2, 2025
Last week, the 7-day precipitation total for the period 8/24/2025 through 8/31/2025 was approximately 0.0 inches in the Cedar River watershed and 0.02 inches in the South Fork (S.F.) Tolt River watershed.
Chester Morse Lake at the Overflow Dike was at an elevation of 1549.8 feet, about 0.3 feet lower than last week and about 1.9 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 1737.3 feet, about 2.5 feet lower than last week and about 8.0 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 168 million gallons per day (mgd). That is more than the 141 mgd consumed during the same period last year, and more than the 159 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 for this summer. As always, we continue to ask customers to use water wisely. For information about ways to save water, visit www.savingwater.org.