The two devices
| Hydromechanical grease trap | Gravity grease interceptor | |
|---|---|---|
| Where | Indoors, under or beside one sink | In the ground outside, with manholes |
| Size | 20–100 gallons | 750 gallons minimum in Reno and Sparks, two compartments |
| How it works | Flow control slows water so grease floats fast | Still water in a large volume; grease floats, solids settle |
| Who may service | Staff or contractor | “A licensed plumber or contractor” (12.16.555(b)(6)(ii)c) |
| Reno’s position | “Shall not be permitted in lieu of a gravity interceptor” ((b)(4)) | Required for food service industrial users ((b)(3)) |
The exception
A FOG variance lets the director “allow the installation of a grease trap or continue to allow the use of an existing grease trap in lieu of installing a grease interceptor where the grease trap is shown to be effective” (12.16.555(b)(5)). The burden is on the facility, and a variance may come with conditions such as quarterly cleaning of your private service line. Sparks is blunter: traps are “prohibited unless approved by the public works director” (SMC 13.30.020(E)).
Why the code prefers the tank
A 40-gallon trap behind a fryer line reaches 25% in two to five weeks and depends on someone remembering. A 1,000-gallon interceptor pumped by a contractor on a permit schedule produces a trip ticket every time, and the city can read the file. The ordinance is built around the paper as much as the plumbing.
If you have a trap today
You are on a variance, or you should be. Keep it effective: full service on a short interval, a dated receipt each time, and a plan for an interceptor if the menu grows. Trap service →