Does my Phoenix restaurant have to comply with the FOG (grease) program?

The program treats every food-service kitchen as a potential grease source, so the requirements are about prevention, not paperwork alone. A compliant Phoenix restaurant generally has to do four things.

• Install an approved grease interceptor. Your kitchen drains that handle grease, including pot sinks, prep sinks, dishwashers, and floor drains in cook lines, must route through a grease interceptor sized for your flow. The City reviews the size during permitting; an undersized unit fails because it fills too fast to do its job. For sizing detail, see how to choose a grease interceptor for a restaurant.
• Clean and pump it on schedule. A grease interceptor only works when there is room inside it to trap grease. The widely used 25% rule says you clean the unit once the floating FOG and settled solids reach 25% of its working volume. Many cities pair that with a minimum interval, such as every 30 days for a small under-sink unit or every 90 days for a larger outdoor tank. See how often to pump a grease trap for how to set yours.
• Keep maintenance and manifest records. Each time the interceptor is serviced, your hauler should leave a manifest showing the date, the volume removed, and where the waste went. Cities commonly require you to keep these for three years and produce them on request.
• Keep FOG out of the sewer. No grease, oil, or fat may go down the drain to the City sewer. That includes the indirect route of using enzymes, bacteria, or solvents to "dissolve" grease, which is prohibited.

It is tempting to think a product that makes grease disappear from your sink solves the problem. It does not. Enzyme, bacteria, and solvent treatments do not remove grease from the waste stream; they emulsify or liquefy it so it slides past your interceptor and back into the City sewer. Once it cools in the cooler public pipe, it hardens again and coats the line. Phoenix prohibits this practice in its FOG Best Management Practices Manual for exactly that reason.

This is the commercial side of a rule that also reaches homeowners. For the home-maintenance angle on why these products fall short, see whether enzyme drain cleaners work. The short version for a food-service operator is that an interceptor that is "kept clear" by chemicals is not being maintained; it is being bypassed, and the grease is still leaving your property.

A grease interceptor is a settling device. Wastewater slows down inside it, grease floats to the top, solids sink to the bottom, and cleaner water passes out the middle to the sewer. Anything that breaks grease into a fine suspension defeats that physics. That is why the program is built around physical removal and recordkeeping rather than additives.

There is also a downstream cost to your neighbors and to the City. Grease that leaves your kitchen does not vanish; it travels through the public collection system and tends to settle where the pipe slows or turns. Over time it can form a solid mass that narrows the main for an entire block. When that happens, the backup may not surface at your property at all, which is part of why the City treats the source, your interceptor, as the point of control rather than waiting for a spill.

Grease is the single largest cause of sewer blockages, and blockages are what cause raw sewage to back up into buildings or spill into streets. The numbers come from the EPA's national study of sewer overflows. In its Report to Congress on the Impacts and Control of CSOs and SSOs, the EPA found that grease was responsible for 47% of reported sewer blockages, more than roots or debris. Blockages, in turn, were the largest single known cause of sanitary sewer overflows.

The EPA is direct about the scale of the problem. The agency states:

"There are approximately 23,000 to 75,000 sanitary sewer overflows per year in the United States."

That same EPA study noted that in the arid Southwest, nearly three-quarters of overflow events with a known cause were caused by blockages, which makes the issue especially relevant to a Phoenix kitchen. When a restaurant's grease helps plug a public main, the overflow that follows can flood a dining room, close a kitchen, and trigger an environmental cleanup. The FOG program exists to stop that grease at the source: your interceptor.

Non-compliance is not a quiet risk. The City inspects food-service establishments, and an inspector who finds a missing interceptor, an overfull tank, no maintenance records, or evidence of prohibited additives can issue a violation. Common consequences include:

• Notices of violation and fines. Repeat or unresolved problems usually escalate, with penalties rising for each step.
• Orders to install or upgrade equipment. If your interceptor is missing or undersized, the City can require you to put in a compliant unit on a deadline.
• Liability for a sewer overflow. This is the expensive one. If your grease contributes to a backup, you can be held responsible for the cleanup of your own property, damage to neighbors, and the City's costs to clear the main. A single overflow can dwarf years of routine pumping.
• Risk to your operating standing. A kitchen that cannot pass plumbing inspection has a problem that overlaps with its health inspection requirements, and unresolved issues can threaten the ability to keep serving food.

Treat the interceptor like any other piece of required equipment. The cost of a scheduled pump-out is small next to the cost of a backup or a fine. A blocked line during service hours can also force you to close the kitchen until it is cleared, so the loss is rarely limited to a single repair bill.

Inspectors generally look for a few specific things: that the interceptor exists and is the size the City permitted, that it is below the 25% rule threshold, that your service manifests are current and on hand, and that no prohibited additives are in use. A kitchen that can show a clean tank and an organized record file usually clears an inspection quickly, while a missing record or an overfull unit is what turns a routine visit into a violation.

Getting compliant is a short list of steps, and most of them are one-time or routine once set up.

1. 1Confirm what you have. Locate your grease interceptor, find its capacity, and check whether it was permitted at the size your kitchen needs. If you are not sure it exists or is plumbed correctly, have a licensed commercial plumber inspect it.
2. 2Set a cleaning schedule. Apply the 25% rule and pick an interval that keeps the unit below that line. A high-volume kitchen may need monthly service; a lighter operation may run longer. Document the schedule.
3. 3Use a licensed hauler and keep the manifests. Hire a permitted grease hauler, keep every service manifest, and store the records where an inspector can see them. Three years is a safe retention window.
4. 4Stop using prohibited products. Remove enzyme, bacteria, and solvent "drain treatments" from your grease-management routine. They are not a substitute for cleaning, and they are not allowed.
5. 5Train your staff. Scrape plates and pans into the trash, dry-wipe greasy cookware before washing, and use drain screens. Less FOG entering the system means longer intervals between cleanings.

A commercial plumber who works with Phoenix food-service accounts can size and service the interceptor, jet the lines if grease has already built up, and help you keep the records that prove compliance.

This page explains how the program generally works, but FOG rules and cleaning intervals are set locally and change over time. Confirm the current requirements that apply to your address with the City of Phoenix Water Services Department and the latest version of Phoenix City Code Chapter 28 before you rely on a specific schedule or interceptor size. Verifying with the City is the only way to be certain your kitchen is covered.