Do you need a permit to replace or add a grease interceptor?

Yes. Phoenix sends every installed or replaced interceptor through plan review, with a small over-the-counter lane for the simplest swap. The FOG manual says: "Per plumbing code all grease interceptors installed and replaced in the City of Phoenix must go through plan review." It gives the reason too. Review makes sure the interceptor is sized correctly, is approved for use in Phoenix, and that all grease bearing fixtures are plumbed to it.

There are two lanes.

### Which jobs can go over the counter?

Appendix B sets two conditions. The job must be small and involve plumbing only. And for grease interceptors, only like for like replacements can be done over the counter. The manual's main text says like for like replacements of hydromechanical interceptors can go over the counter. The manual does not define like for like, so ask the reviewer if your new unit differs in size or type.

Appendix B also says that if all the plumbing stays the same and only the pretreatment device is different, only a plumbing floor plan layout is required.

### Which jobs need full electronic review?

Any plans that require major plumbing changes, including installation of a new grease interceptor, cannot be submitted over the counter. They go through electronic plan review. If any re-piping is involved, the drawings must include a plumbing floor plan layout and an isometric drawing. The manual's example is a fixture that must be rerouted or a new fixture added. The isometric must show pipe size and venting.

So a trap-to-tank upgrade is a full review. See when a grease trap has to become an interceptor.

### What must the Phoenix submittal include?

Appendix B lists the basics.

1. 1The name and address of the business, with the suite number when there are several suites.
2. 2All existing grease bearing fixtures in the restaurant.
3. 3Plans showing that all of them are routed to an appropriately sized trap or interceptor.
4. 4An orientation mark, such as an indication of north.
5. 5The manufacturer and the model number or size of the device. All devices must be pre-approved by the Environmental Services Division.
6. 6For a gravity interceptor, an approved model. The smallest allowed is a 2-compartment, 2-man-way, 500 gallon unit.
7. 7For a trap, a device that is PDI or IAPMO approved, or UPC listed.
8. 8A copy of the Commercial Inspection Report, if an inspector required the device.

Two more notes from the manual. A certificate of occupancy is required for all plan reviews. And all drawings must be legible or the review will be denied.

Appendix B asks you to call at least 24 hours in advance so an Environmental Services Division inspector can be on hand for that part of the review. Phoenix's construction plan review page describes the general process: you submit plans and the application, staff review them, corrections are sent back if needed, and the permits are issued after fees are paid. The page also lists a SHAPE PHX portal, and it gives a commercial line for questions. Appendix B describes its own counter and upload steps, so confirm the current route with the city before you file.

Most of them ask for the same things at different points. Here is each one.

### Scottsdale

The submittal list in Scottsdale's guidelines is blunt. Grease interceptors shall not be allowed to be installed at risk. Plans may be required to be prepared and stamped by an Arizona registrant. Calculations must follow the city's method under the amended 2021 IPC. If a gravity interceptor is required, site plans and civil drawings are required along with two copies of all documents, showing all setbacks and public utility easements. All work must be performed by a licensed plumbing contractor per ROC requirements.

### Mesa

The Mesa plumbing plan checklist, written to the 2024 IPC, asks you to provide the required grease or sand and oil interceptors and their locations. Its interceptor section says grease interceptors shall be reviewed and approved before installation, and it sends you to Industrial Pretreatment.

### Tempe

Tempe's pretreatment code covers grease devices as pretreatment devices. Section 27-21 says detailed plans describing pretreatment facilities shall be submitted to the Public Works Director for review and shall be acceptable to the director before the facilities are constructed. Section 27-22 says traps and interceptors must be installed in compliance with Chapter 8 of the city code and the city's rules and procedures. Tempe's FOG page also links an interceptor installation detail and a sizing spreadsheet.

### Chandler

Chandler's page says have your plumber provide a fixture count and a plumbing plan to Development Services when applying for the plumbing permit. The fixture count is what sizes the device.

### Gilbert

Gilbert's code requires every newly constructed, remodeled or converted commercial facility with grease generating activities to install a grease removal device at least as large as the plumbing code requires, and says the sizing criteria are available at the public works wastewater quality branch. The section we read does not spell out the permit steps, so ask the town how a swap is filed.

### Surprise

Surprise lists shops that may install a grease trap in place of an interceptor, such as delis and coffee shops, but only with calculations submitted and sealed by an Arizona certified professional engineer. Its page does not describe a permit process, so start with the city's pretreatment staff.

### Does the county health department also review it?

Maricopa County Environmental Services runs its own plan review for food establishments, and its construction guide leaves grease device sizing to the city. The guide says local municipalities determine the number and size of grease traps, grease interceptors or catch basins. It adds that grease traps must be spaced so they are easily accessible for servicing and cleaning. That means two reviews can touch the same room, and our page on county restaurant plan review shows how they fit.

### Who can do the work?

Scottsdale says all work must be done by a licensed plumbing contractor per ROC requirements. Our page on who can pull a commercial plumbing permit in Arizona covers the wider rule. Ask any bidder which grease permits they have filed in your city and what the reviewer asked for.

### What does routine pumping need?

The manual's plan review language covers installing and replacing interceptors. It says nothing about routine pumping. Pumping and records are a separate track under the FOG program; see Phoenix's FOG program page.

Plan first, dig second. Here is the sequence most Valley cities expect.

1. 1Count the fixtures and decide trap or interceptor with your city's rule.
2. 2Pick a device from the city's approved list, where one exists.
3. 3Choose the location; see where an interceptor can go.
4. 4Submit for review before any digging.
5. 5Install, then schedule inspections. The installation steps walk through that stage.

Sizing math for the submittal is in how an interceptor is sized, and what size a restaurant needs gives the overview. If the reason for the job is a failed part, a broken baffle or outlet tee may be a repair, but the city decides whether the repair needs review.

Call before you dig. A licensed plumber can prepare the fixture count and drawings, and can tell you which lane your job is in. HQ is licensed and insured, gives free estimates with the price set up front, and offers 24/7 emergency service. See our commercial plumbing page.

Replacing a tank because the concrete has rotted? See why concrete grease interceptors corrode. If your city wants a sample tee or vault on the new unit, see grease interceptor sampling ports.