Cascade Water Alliance

Lake Tapps 
Public Water Supply Project

Lake Tapps
Boat Management

Lake Tapps
Watercraft Usuage


Lake Tapps milfoil treatment scheduled for 
week of August 7

Cascade Water Alliance, owner of Lake Tapps, continues its multi-year program to address milfoil growth by treating the infestation scheduled for the week of August 7. The property owners within the treatment zones and a short distance beyond the treatment zones will be notified at their home regarding this treatment.

Four areas on the lake will be treated with Sonar Aquatic Herbicide.  This product will be applied between two and three times at approximately one month intervals.  A fifth area will be treated once the week of August 7 with Renovate OTF herbicide.

Eurasian milfoil is a non-native invasive plant. Although it is no longer required that Cascade treat this species, Cascade continues to treat milfoil to ensure a clean and healthy lake. Divers have been doing hand pulling in some areas for weeks.

A treatment map is viewable at this web link.  Residents can enter their address and determine if they are within or close to the treatment zones.  Treatment Map Click Here

There are no swimming restrictions on the treatment zones for SonarOne. However, there is a 24 hour swimming precaution in the Renovate treatment area. 

Native vegetation will not be treated by Cascade. Fertilizer and septic tanks that are not well maintained contribute to the growth of this vegetation, and homeowners should use natural yard care and regular maintenance of septic systems.

For more information on the treatment visit

For more information about Cascade Water Alliance visit

Lake level to rise to 543 feet

This week Cascade Water Alliance will raise the Lake Tapps reservoir to approximately elevation 543 feet, the maximum allowable level Cascade can operate Lake Tapps. 

Cascade raises the lake to the maximum allowed at least once each year as a reminder to homeowners of the maximum fill level.   After the maximum fill, Cascade keeps the reservoir between elevation 541.5 and 543 feet, usually about 542.7 feet, from about mid-April through late September.

For the latest in lake level information and for the agreements regarding lake levels please visit 

For more information on Lake Tapps / Cascade agreements visit

For more information on Cascade visit

Algae Watch, Alerts and Information

Tacoma-Pierce County Health Department tracks Lake Tapps for possible toxic algae or bacterial contamination.

If you would like to learn more or get involved in Algae Watch, please email:

If you would like to receive alerts about environmental or human health concerns at area waterways, sign up at:

For more information about toxic algae, go to:

Call: (253) 798-6470.

Lake Tapps Reservoir is a beautiful recreational area, but it is also part of Cascade Water Alliance’s water supply system, including the lake bed (up to elevation 545 feet), the dikes, and the entire White River system.
To keep a healthy, safe reservoir, the following regulations are in place for recreational and public access:

Dikes: Dikes are closed to the public, accessible only by homeowners whose property abuts the dikes or if one has a license issued by Cascade.  All other presence on dikes is trespassing. Unlicensed structures on dikes will be removed at owner cost.

Lake Bed: To build or remodel bulkheads or docks, a Cascade license and all appropriate permits must be obtained before work can start. Unpermitted structures will be removed at owner cost.

Closed Areas: Trespassing on the dikes, within the White River Project, or on Cascade areas posted “no trespassing” will be referred to law enforcement agencies. This is for safety.
Cascade and its partners in law enforcement, fire and schools remind swimmers that the reservoir is glacier fed, and is therefore often very cold in some places. Recreation enthusiasts should call 911 if they spot trouble on the lake, trespassers, speeders, violators or people in damage.  

To assist homeowners in planning ahead for project work, Cascade has issued the following lake level plans (subject to change due to unforeseen circumstances).  The reservoir level in the summer is 542.5 feet, and most winters it is 539.5 feet.  However, in winter 2018-19, it will be down to between 530 – 532 feet for project work. 

For more information about Lake Tapps, visit 
To obtain a license for work on your property visit 
For who to call around the lake visit 

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Bear in Boat



Emergency: 911
253 798 4721

Option '1'

Pierce County Sheriff
Boating Hotline:
253 798 3300

Lake Tapps Hotline
253 891 5460

Cascade Water Alliance
877 299 0930


City of Bonney Lake
253 447 4344


Pierce County
Planning and Land Service
253 796 7210

Washington State
Fish and Wildlife

360 902 2200