Important update on Lake Tapps Reservoir water levels

Cascade’s Lake Tapps Reservoir conveyance system project is underway. No water has been added to the reservoir since late August and residents may already be noticing lower water levels. Residents should take note of the unique conditions in their locations to decide when to remove boats from the reservoir, especially in shallow bays or coves. Some areas may become too shallow for some uses more quickly than others, and homeowners should watch the water levels and act accordingly.  

In August, Cascade filled the Lake Tapps Reservoir to its highest allowable level (approximately elevation 543 feet) and closed the project headgate for inspection and repair work on the facilities that make up the conveyance system to the reservoir. No water has been added to the reservoir since then (other than rainfall) and Cascade has minimized water released through the tailrace to keep the reservoir as full as possible through the end of the recreation season on September 30, while work is being carried out upstream. The project will improve the reliability and water quality of the water that flows through the conveyance system to the Lake Tapps Reservoir.

The reservoir will slowly drawdown between now and the end of October, with no added water coming into the system other than rainfall. Cascade will begin active fall drawdown on November 1 and will bring the reservoir level down to approximately 539 feet for the fall and winter.  This drawdown is necessary for the integrity and maintenance of the dikes and to ensure safety from wind, storm, and wave action during the winter months.

Residents can monitor overall reservoir water levels by clicking here.

Cascade maintains seasonal recreational water levels between elevation 541.5 feet and 543 feet from April 15 to September 30.  The 2022 spring refill is anticipated to begin in mid-February.

For more information about Cascade and Lake Tapps visit  and for information regarding licenses for project work visit