Code Applied by the app plumb.waste.grease-interceptor
Grease interceptors
Kitchen, dish and bar fixtures that carry grease drain through a grease interceptor, and the restrooms join the sewer downstream of it, because the interceptor is for grease-laden waste only.
| When | The app uses |
|---|---|
| fixtures and equipment with grease-laden waste in a food preparation area (a restaurant, a kitchen, a bar) | through a grease interceptor |
| water closets, urinals, lavatories and other fixtures without grease | kept out of the interceptor |
- Source
- IPC · 1003.3.1 Grease interceptors and automatic grease removal devices required · read the public text
- Editions checked
- 2018 · 2021
- Used by
- Courses
- Amendments
No state or local amendment to this rule is on file. Not on file means the model code as written — check your jurisdiction.
A model code the authority having jurisdiction adopts.
In a grease interceptor the kitchen's waste slows down, the grease floats and cools, and a truck pumps it out on a schedule. Only waste that carries grease belongs in it: the three-compartment sinks, the dish pit, the floor drains and floor sinks in the kitchen and the bar. Sanitary waste from the restrooms would fill it with what it cannot separate, so the restrooms go around it and join the sewer downstream.
On a bid that is two waste systems, each with its own pipe to the sewer, and the interceptor itself: a large precast or steel tank outside, with its excavation, its covers and its sampling point, often priced on its own line.
What the app does with it
Nothing yet: the app does not apply this rule. It is on a course card (the plumbing course, Chapter 4, "Waste on its own layer"), which has you trace the grease line and the sanitary line apart. The app does not know which fixtures carry grease or check what drains through the interceptor.
Verify against your edition
1003.3.1 requires a grease interceptor or an automatic grease removal device for grease-laden waste in food preparation areas, names the fixtures (pot sinks, prerinse sinks, kettles, wok stations, the floor drains and sinks kettles drain into, hood wash units, dishwashers without a prerinse sink), and says in its own words that an interceptor receives waste only from fixtures and equipment that allow fats, oils or grease to be discharged. The Uniform Plumbing Code says the other half outright, that water closets, urinals and other fixtures carrying human waste do not drain into or through one (1014.1 in the 2018 edition), and the local sewer authority usually says it too. A food waste disposer is kept out of an interceptor too, with an exception for a large gravity interceptor (1003.3.2). Interceptor sizing is the sewer authority's and the engineer's, not this rule's. Settled 2026-09-27 by Claude on the owner's delegation, from the dossier's research and the model code text; not checked against a printed book or a local amendment.
Cited by section, not reprinted: the code text belongs to its publisher. Company practice is not a rule here — it lives with your pricing.