Sandy reviews wastewater treatment options as regulators, costs and timelines constrain local fixes

Councilors and consultants on March 3 held a workshop on Sandy’s long-running wastewater challenges, reviewing what analyses have been done, which options are viable and the timetable and price pressure facing any solution.

City staff and Stantec consultants said the central constraint is how and where treated effluent can legally and practically be discharged. Heather Stevens, a Stantec wastewater planner, said Oregon rules limit how much effluent can enter small receiving streams and that the commonly cited “three‑basin” limits and a roughly 10:1 dilution requirement are key constraints. Stevens said those state water‑quality rules and dilution limits make continuing to rely on Tickle Creek difficult in the long term.

Stantec program manager Jake Talley said reinvesting in the existing treatment plant would buy time but would not be a permanent fix. Talley said recent flow monitoring and modeling indicate even an upgraded plant would likely exceed the state dilution limit in about 10–14 years because local stream flows are declining while wastewater volumes increase. “It buys us a little time, but it doesn’t fix the problem,” Talley said.

Why it matters

The discussion matters because the city is under an enforcement agreement with federal regulators and must find a compliant, sustainable path for treated effluent as growth and seasonal variability reduce the creek’s capacity to accept wastewater. City staff repeatedly told the council that…