Commercial Plumbing: Rules in Phoenix-Area Cities
Grease interceptors, FOG programs, industrial wastewater and tenant improvements. City by city, then the Arizona law and model code behind it.
By City
| City | What the rule says |
|---|---|
| Phoenix | Phoenix City Code Chapter 28: The FOG (Grease) Program for Food-Service Businesses Phoenix City Code Chapter 28 bars food-service businesses from putting fats, oils, and grease into the city sewer. Under the City's FOG program, a restaurant must install an approved grease interceptor, pump it on schedule, keep service records, and pass city inspections. |
| Phoenix Industrial Wastewater Discharge Permit (City Code Ch. 28) An industrial or commercial business in Phoenix that sends process wastewater to the public sewer usually needs a city wastewater discharge permit first. Phoenix City Code Chapter 28 and its Industrial Pretreatment Program set the rules. This is separate from the FOG grease program, which covers food-service kitchens. |
Uniform Plumbing Code
All UPC sections- Model Code · Updated Jul 2026UPC 1007: Trap Seal Protection for Floor DrainsUPC Section 1007 covers trap seal protection for floor drains. A seldom-used floor drain can dry out as its trap water evaporates, which lets sewer gas into the building. The fix is an automatic trap seal primer that adds water to the trap, or a barrier-type device. These must meet ASSE 1018, ASSE 1044, or ASSE 1072.
- Model Code · Updated Jul 2026UPC 422: How Many Plumbing Fixtures a Building Must HaveUPC Section 422 and Table 422.1 set the fewest plumbing fixtures a commercial building must have. The count runs off the occupant load and the occupancy group, so a busy restaurant needs more toilets, sinks, and drinking fountains per person than a quiet office. Separate facilities for each sex are generally required above a set occupant load.
- Model Code · Updated Jul 2026UPC 803: Indirect Waste PipingUPC Section 803 covers indirect waste piping, the drain line that empties over an open receptor through an air gap or air break. Ice machines, coolers, food-prep sinks, and similar equipment must discharge this way, never straight to the sewer. The code also limits how long the pipe may run.
- Model Code · Updated Jul 2026UPC Grease Interceptor Sizing: How Code Sizes a Grease TrapPlumbing code sizes a grease interceptor from the fixtures that drain into it, so it is large enough to trap fats, oils, and grease before they reach the sewer. Sizing uses the drainage load and flow of the connected sinks and equipment, with a minimum size for gravity interceptors serving a commercial kitchen.
Need The Work Done To Code?
Call a licensed plumber who pulls the permit in your city and passes inspection the first time.