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What Is FOG? Understanding Fats, Oils & Grease in Restaurants

FOG is the fats, oils, and grease produced during cooking and dishwashing that can clog pipes, disrupt sewers, and trigger compliance issues.

Published July 20, 2026 · Grand Natural Inc.

What Is FOG? Understanding Fats, Oils & Grease in Restaurants

FOG Defined: What the Abbreviation Means

FOG stands for fats, oils, and grease. In the restaurant and food-service world, it refers to the organic byproducts that come from cooking meats, frying foods, preparing sauces, washing dishes, and cleaning equipment. FOG can be liquid when hot, but it often cools into a thick, sticky solid that coats pipes, drains, and sewer walls.

Not all FOG looks the same. It includes bacon grease and fryer oil, but it also includes salad dressings, dairy fats, butter, shortening, and fatty food scraps rinsed off plates. Even small amounts washed down a sink can add up quickly in a busy kitchen.

Where FOG Comes From in a Restaurant Kitchen

FOG enters the waste stream from many everyday tasks. Understanding the sources helps kitchen staff spot problems before drains slow or back up.

Hot water and detergent may keep FOG liquid long enough to leave the sink, but once it hits cooler sewer lines, it can separate and cling to pipe walls.

Why FOG Is a Problem for Restaurants

FOG is one of the most common causes of costly plumbing and sewer issues in food-service operations. When grease cools, it hardens into blockages known as fatbergs, which reduce flow and can cause backups into kitchens, parking lots, or streets.

The risks go beyond inconvenience:

Preventing these problems starts with treating FOG as a waste stream that requires its own handling routine, not something that can simply be rinsed away.

How FOG Regulations Affect Restaurants

Most cities and sewer districts have rules limiting how much FOG a commercial kitchen can discharge into the sanitary sewer. These rules vary widely, but they typically cover grease-trap sizing, installation, maintenance frequency, recordkeeping, and allowable discharge limits.

Common requirements include:

Because rules differ by municipality, always check with your local sewer authority or environmental health department for the standards that apply to your location.

Best Practices for Managing FOG in Your Kitchen

Good FOG management is part of daily kitchen culture. Small habits prevent big problems.

Used cooking oil recycling also supports sustainability efforts. Recycled oil can be refined into products such as biodiesel, animal feed, and industrial materials, turning a waste problem into a resource.

When to Bring in a Professional

Even with strong in-house practices, most restaurants need outside help to stay ahead of FOG. A qualified service provider can pump grease traps and interceptors, clean kitchen exhaust hoods and ductwork, jet clogged lines, and collect used cooking oil for recycling.

Look for a provider that understands your local requirements, documents every service, and can support your schedule during busy periods. Companies like Grand Natural work with restaurants to manage FOG through used cooking oil collection, grease trap cleaning, and related kitchen waste services. Whether you handle everything in-house or partner with a specialist, the goal is the same: keep FOG out of the sewer and your kitchen running smoothly.

Conclusion

FOG may be a normal byproduct of cooking, but it is not a normal part of your wastewater. Knowing what fats, oils, and grease are, where they come from, and how to control them protects your plumbing, keeps you in compliance, and reduces costly surprises. Build FOG awareness into your daily routine, follow local rules, and work with experienced professionals when needed.

Need service for your kitchen? Grand Natural provides used cooking oil collection, grease trap cleaning, hood cleaning, and kitchen line jetting to restaurants nationwide. Call (855) 519-5550 or request service online.

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