Cascade Water Alliance has announced the 2026 Lake Tapps Reservoir drawdown. The current reservoir elevation is 540.55 feet. Cascade will continue to monitor the weather and river flows throughout the month of October and will add water to the reservoir if possible. Cascade will begin the active fall drawdown on November 1 and will bring the reservoir level down to approximately 538-539 feet elevation for the fall and winter. The drawdown allows Cascade to perform necessary maintenance on the dikes and ensures safety from wind, storm, and wave action during the winter months. Residents should watch reservoir levels and make appropriate decisions regarding removing boats and other property from the water.
The statewide drought made maintaining reservoir levels difficult this summer. Cascade captured flows from the White River in August when a stretch of warm weather provided glacial melt and higher flows in the river. However, due to the continued statewide drought and lower than normal river flows, Cascade could not add any significant water to the reservoir over the last month, so levels dropped. Cascade’s state-granted water rights do not allow any water diversions to the reservoir when the river is below certain levels, called minimum instream flows, like it is now.
The 2027 spring refill is anticipated to begin in mid-February, and Cascade plans to raise the reservoir to approximately 543 feet during the spring. This is the maximum allowable fill level at which Cascade can operate under operating agreements with the Lake Tapps Community Council.
If residents are planning work on their property, this is a good time to obtain the appropriate, required permits and a Cascade license prior to beginning any work. Further, residents should keep in mind as they do work on their property, especially bulkheads, that Cascade has the authority to raise reservoir levels to elevation 543 feet under current water rights, so any new or modified bulkheads should be built with the consideration that the reservoir level will be up to 543 feet.
For more information about Cascade and the Lake Tapps Reservoir, visit cascadewater.org.
For information regarding licenses for project work, visit cascadewater.org/lake_tapps_licenses_and_permits.php.