Understanding Commercial Grease Traps: Types and Functionality

September 3, 2023 in plumbing

Understanding Commercial Grease Traps: Types and Functionality

When it comes to keeping your commercial kitchen running smoothly in San Diego, California, one crucial aspect to consider is a grease trap. Grease traps are essential for maintaining a clean and efficient plumbing system in restaurants, cafeterias, and other food-related businesses. In this article, we’ll delve into the various types of commercial grease traps and how they work to safeguard your plumbing system and the environment.

Types of Commercial Grease Traps:

Gravity Grease Traps:

Gravity grease traps, also known as passive grease traps, are the most common type found in commercial kitchens. They rely on the principle that fats, oils, and grease (FOG) are lighter than water and will naturally separate. These traps consist of two chambers – an inlet for wastewater and an outlet for treated water. As wastewater enters the trap, FOG rises to the top, and cleaner water flows out through the outlet. Periodic maintenance, including regular cleaning, is essential to prevent clogs and maintain their effectiveness.

Hydro-Mechanical Grease Traps:

Hydro-mechanical grease traps are a step up from gravity traps in terms of efficiency. These traps use a combination of mechanical features and water flow to separate FOG from wastewater. As water enters, a rotating mechanism skims the grease off the surface and collects it in a separate chamber. These traps require less frequent maintenance compared to gravity traps and are suitable for busier commercial kitchens.

Automatic Grease Interceptors:

Automatic grease interceptors are the most advanced option, ideal for high-volume restaurants and food processing establishments. They use advanced technology to continuously monitor FOG levels and automatically remove it from wastewater. This not only reduces the risk of blockages but also helps businesses comply with environmental regulations.

How Does a Grease Trap Work?

Wastewater Entry:

All wastewater from sinks, dishwashers, and other kitchen appliances flows into the grease trap. As the water enters, it moves through a series of baffles or plates that slow down the flow and allow FOG to separate from the water.

Separation of FOG:

Inside the grease trap, the FOG, being less dense than water, naturally floats to the top. Solid food particles settle at the bottom, leaving relatively cleaner water in the middle.

Retention and Skimming:

In gravity traps, FOG accumulates at the top until it’s manually removed during routine maintenance. In hydro-mechanical traps, a skimming mechanism removes FOG continuously, preventing excessive buildup.

Cleaner Water Discharge:

After FOG separation, the cleaner water in the middle is allowed to flow out of the grease trap and into the sewer system or septic tank. This cleaner water poses fewer risks to your plumbing and the environment.


In San Diego, California, where the restaurant industry thrives, understanding the types of commercial grease traps and how they work is vital for smooth kitchen operations and compliance with local regulations. Whether you opt for a gravity trap, a hydro-mechanical trap, or an automatic grease interceptor, proper maintenance and regular cleaning are essential to keep your plumbing system free from clogs and your business environmentally responsible. If you need assistance with grease trap installation, maintenance, or repairs, don’t hesitate to contact Abe Plumbing for professional and reliable service.