Cascade Water outlines $1.1–$1.35 billion supply plan and warns of multi‑year rate pressure

Representatives of the Cascade Water Alliance briefed the Issaquah City Council on Aug. 3 about an early‑stage, multi‑decade Cascade Supply Program to connect regional water sources, build a large transmission pipeline and associated storage and treatment facilities. Brian Bartle and Andy Baker said the program is at pre‑planning and carries high uncertainty, but they presented a cost range of $1,100,000,000 to $1,350,000,000 that includes a 20% management reserve.

Andy Baker said the recommended capital funding strategy would require significant rate increases for Cascade member charges and described a scenario that includes 9.5% charge increases in 2027 and 2028; municipal impacts will depend on the city’s share of purchased water and the timing of passthroughs. Emily Moon, Issaquah’s public works director, said the city currently anticipates an Issaquah rate impact in the mid‑single digits in the near term and estimated a 6–7% first‑year increase in local rates tied to the Cascade schedule.

The presentation prompted detailed council questioning about alternatives (desalination, expanding local wells, wheeling), timing and options to reduce cost. Cascade said desalination is currently cost‑prohibitive and environmentally constrained and that Seattle has declined to “wheel” water through its infrastructure; Cascade staff emphasized pursuit of federal financing tools (WIFIA, potential earmarks) and a robust cost‑control committee. Councilmembers pressed for additional regional coordination and asked staff to pursue federal funding and oversight mechanisms.

Quotable: “We are showing a cost range for this program ... between 1,100,000,000 and $1,350,000,000,” Cascade staff said during the briefing. Councilmembers described the numbers as sobering and stressed transparency as the process continues.