Cascade Supply Program

Cascade Water Alliance is excited to undertake a historic program to provide a resilient water supply to our member agencies.  The Cascade Supply Program, or CSP, will change the regional supply of water through a future connection with Tacoma Water.

Cascade’s supply contract with Seattle is a declining block agreement, which begins to decline in 2039. Without a contract extension with Seattle, or a new supply contract with Tacoma or other supplier, Cascade would need to develop and put the Lake Tapps Reservoir in service by 2042.

In May 2024, Cascade’s Board of Directors approved a resolution which directed Cascade to negotiate a supply contract with Tacoma. In January 2025, the Board approved a resolution for Cascade’s CEO to finalize and execute two new supply contracts with Tacoma. The Tacoma City Council is expected to approve the contracts by the end of March 2025. Cascade expects to take water from Tacoma starting in 2041 to replace the declining Seattle supply.

A new contract with Tacoma would allow Cascade to defer developing the Lake Tapps Reservoir until at least the 2060s. By that time, Cascade would need a new water treatment plant and other major infrastructure.