Cascade Announces 2023 Lake Tapps Milfoil Treatment Plan

Cascade Announces 2023 Lake Tapps Milfoil Treatment Plan

Cascade conducted milfoil surveys in May and June. Based on these surveys and information received from residents throughout the year, Cascade is announcing its 2023 planned milfoil treatment.

The areas designated to receive treatment are marked on the attached map. Treatment is tentatively set to begin in the next two weeks. Residents in planned treatment areas will be notified regarding time and dates of treatment prior to actual application.

Cascade will be using the State Department of Ecology approved aquatic herbicide ProcellaCOR®. Cascade used this herbicide to treat the reservoir for the past four years with good results. It is environmentally friendlier than herbicides used in the past, and results have been significantly better. This treatment may affect water that is used for irrigation, but, as a reminder, pumping or drawing Lake Tapps Reservoir water for irrigation is never permitted.

Although Cascade is able to treat much of the milfoil in the reservoir, it doesn’t have the funds to treat all impacted areas, such as small patches that affect a limited number of homeowners. In response to requests from the community, Cascade’s Board of Directors has authorized a pilot project for 2023 for additional treatment.

The 2023 pilot project allows homeowner associations (HOAs) and individual homeowners to use Cascade’s permit and contract directly with Aquatechnex to chemically treat milfoil in front of their residences. Treatment will be limited to milfoil and will not include other non-native or native plants. Aquatechnex will likely perform two rounds of treatment – one in June and one in July/August.

For more information about the pilot and to sign up, go to

Milfoil is found in most Northwest lakes. It has been in Lake Tapps on and off for years. Milfoil is no longer classified as a noxious weed, and therefore, Cascade has no legal obligation to address milfoil. However, Cascade is as interested as residents and recreation enthusiasts in keeping the reservoir clean and safe. This is why over the past decade, Cascade has treated and addressed milfoil management on a regular basis at its own cost.  Cascade does not manage native vegetation.

If property owners plan to remove aquatic plants from the Lake Tapps Reservoir in front of their property, they must follow the rules outlined by the Washington State Department of Fish and Wildlife (WDFW). Additional information can be found at WDFW Aquatic Plant Removal or Control:  The WDFW rules can be found in the Aquatic Plants & Fish Pamphlet:

In addition, Cascade has teamed up with the Tacoma-Pierce County Health Department to offer residents TappsWise, a natural yard care and septic system maintenance program to keep the

Lake Tapps Reservoir clean and healthy.  Additional information about TappsWise can be found here:

For more information visit