The rule
“Hydromechanical grease interceptors (grease traps) shall be cleaned at least every thirty (30) days or whenever twenty-five percent (25%) of the trap volume is occupied by grease and solids, whichever occurs first” (Spokane County Code 8.03.5080.B.1). A 20-gallon trap behind a working line is at 25% in two to four weeks, so for most kitchens the 30 days is the ceiling, not the plan.
What a county-compliant cleaning is
- Grease cap, water and settled solids all out — the device “pumped dry” (B.5)
- Sides, baffles and tees washed; wash water taken away, not tipped back in
- Outlet and flow-control fitting checked
- Refilled with clean water so the seal re-forms
- A record with date and time, volume removed, and who did it (C)
Who may do it
The code lets a trap be cleaned by the business or a contractor; the record requirement is the same either way. Where a kitchen does it in-house, the problem is almost always disposal and the missing record. A monthly route visit costs less than the first notice of violation.
Trap or interceptor?
If your unit is under or beside the sink and holds tens of gallons, it is a trap on the 30-day clock. If it is in the ground outside, with manholes, it is an interceptor on the 90-day clock. Interceptor pumping →