The rule
Spokane County Code 8.03.5080.B.6: enzymes, bacteria, solvents, emulsifiers and surfactants are not permitted as a means of maintaining a grease control device. The clock in B.1 and B.2 is the only approved method.
Why
A trap or interceptor works by letting grease float in still water. An additive breaks the cap into droplets that stay suspended and leave with the water — into your lateral, where they cool and re-congeal, and into the county main. The device reads cleaner; the grease is now the county’s problem, and 8.03.5080.F and 8.03A.0213 make the cleanup cost yours.
What works
Screens and dry-wiping before the sink, used oil to the rendering drum, and the county clock: 30 days for traps, 90 for interceptors, sooner at 25%. Nothing in a bottle.
Plain-English guidance, not legal advice. Quotations are from Spokane County Code
Chapter 8.03 (Sewer Use) and 8.03A (Pretreatment), Municode version dated Sep 11, 2026, read 2026-10-08.
The City of Spokane (SMC 13.03A) and Spokane Valley (SVMC 22.160) publish their own FOG rules through
eCode360, which we could not read directly; where this site describes them it says so. Confirm current
requirements with the county’s FOG program at (509) 477-7579.