Grease Traps

Grease Trap Installation

Grease Trap Installation For Your Commercial Kitchen

Cooking generates a lot of dirt and waste, especially liquid waste. If this waste is left unchecked, it not only becomes disgusting but can also have severe and expensive consequences.
No fats or oils should be poured down a sink as they will turn into a blocked sink and a plumber will need to be called.

In a commercial premises this is even more important with the amount of fats/oils/grease involved in cooking.
It can cause problems at local water treatment plants and clog neighbourhood sewers.
Therefore, pouring FOG (an acronym for fats, oils, and grease) down drains and polluting sewer systems is a bad idea and has adverse effects at many levels.

While it’s easy to pour FOG into an empty can or jar in homes, it’s a pretty daunting task in larger businesses.
This is where a grease trap/grease interceptor comes into play.

A grease trap is crucial to daily operations in any commercial kitchen. All local councils/municipalities mandate it, and a grease trap is necessary for a commercial kitchen to function properly.

What Is A Grease Trap?

First, let’s explain what exactly a grease trap is. It is a container in the wastewater system that collects fats, oils, grease and solids (FOGS) after the wastewater goes down the drain. From here, the clear water is discharged into the wastewater system. Therefore, removing FOGS through grease interceptors is important to reduce the likelihood of sewer system problems such as backups and overflows, which take more time and money to fix. 

grease trap
From Sydney Water Website – Click to see original source

Grease Trap Installation Requirements

There’s no doubt that a grease trap plays a critical role in reducing the damage that FOGS can cause without one, which is especially important when a significant amount of wastewater flows through the sewer system every day. In Australia, grease interceptor standards are in place to ensure that the drainage infrastructure continues to function efficiently, even under intense use and after extended periods. Three of the most important points to consider are:

  • Content of the wastewater
  • Size of the trap
  • Type of trap

For example, an under-sink grease trap in Australia is classified according to three different standards. The three existing standards that are widely used in Australia are:

  • European Standard EN 1825
  • Australian Standard AS 4494
  • International Standard EN 1825

Grease Trap Requirements

Grease traps must be approved before by Sydney Water before they can be installed. See grease trap request form
There is also a list of approved grease traps to select from – See the grease trap list

Grease Trap Install Work

Use a licensed plumber who is skilled in commercial work. Getting the trap installed correctly and so it meets all the requirement issues are vital to avoid a bio hazard disaster down the track

Size Matters

The size of your grease trap needs to be suitable for your current business demands and for how the business grows in the future. 1000 litres in the minimum size to be installed. If you install an undersized grease trap, you may be asked to install additional pre-treatment.

Location Of A Grease Trap

It should be as close to the kitchen as possible. This will prevent pipes clogging if the waste needs to travel a distance to the trap. We all know how fat clogs pipes!!
The grease trap must also be  easily accessible by a vacuum tanker for the ongoing cleaning requirements.

The Law Of Gravity

Water cannot be expected to run up a hill and this applies to all waste water.
A gravity based system will not require additional pump installations. Pumps are expensive and can fail. If a pump fails it means you will have a whole lot of waster water to deal with back flowing into your kitchens.

Backflow prevention
We do a lot of backflow prevention installs and with grease traps they all require one. You can read more about the different types of back flow preventors here.

Safe access
All  grease trap installations require safe access for Sydney Water inspections and for ongoing maintenance work

What Does A Grease Trap Look Like?

The material inside a grease trap contains wastewater and FOG. But what does the separator itself look like? It consists of a baffle wall and the main sewer.

The trap itself is protected by a maintenance hole cover and is usually located in your parking lot or near your building.

Grease traps are usually located outdoors, but smaller traps are also available for indoor use. The idea with the design is to keep the FOG material and the water separate.

How Does A Grease Trap Work?

The beauty of grease traps is their simplicity, as their basic design has remained virtually unchanged for over a century. At its core, it’s a very simple concept: 

Fat, Oil and Grease (aka “FOG”) is lighter than water and therefore floats.

The grease trap is a manhole with an inlet and an outlet to the tank, with baffles placed at different levels to catch the grease as it enters from the drain pipe of a sink. The FOG remains buoyant, and any other larger or heavier food debris sinks to the bottom of the separator. Flow control prevents the water from washing it away into the wastewater system. This natural separation of FOG and water eliminates the need for filters or other separation devices.

Are There Different Types Of Grease Traps?

All grease interceptors/traps serve the same purpose and are similar in design but may differ in size and type of materials used. Grease traps are designed to connect to individual sinks, while larger traps are installed to serve larger facilities. The size of your business, production volume and space requirements will determine what type of trap you need.

There are three types of grease traps for commercial applications: 

  • Passive hydromechanical grease trap (manual)
  • Automatic grease trap
  • Gravity grease traps

Most grease traps for food processing plants are made of lightweight and strong HDPE plastic.
This makes them easy to install and maintain on a regular basis. Concrete grease interceptors are less common but can be specified on installation projects involving a hydraulic consultant.

You Need To Clean Your Grease Trap Regularly

Because your grease trap is constantly filling with cooling oils and fats that turn to solids, there is a risk that they will become trapped and stuck in the unit. It’s simple to understand how a grease trap can quickly become clogged.

The warning signs that your kitchen grease traps need cleaning:

  • Slow sink drainage due to buildup means water can drain slowly, which can quickly lead to bigger problems.
  • Foul odours due to the buildup of fats and oils. 
  • Noisy drains, such as gurgling or growling, indicate that your drain/sink(s) is/are clogged.

Grease Trap Maintenance, Cleaning And Inspection

According to the Water Corporation, as the owner of a business with a grease trap, you are responsible for keeping it clean and pumping it out regularly. 

Pumping out the grease trap can be done at the same time as cleaning or at another time. However, the frequency with which this must be done is specified in the commercial waste permit you receive when the trap is first installed. According to this permit, you must:

  • Ensure that your grease trap is pumped out within the specified timeframes
  • Report the pumping events to the water authority within 7 days of their occurrence
  • Hire a licensed liquid waste contractor
  • Maintain a responsible and healthy use of FOG in your business.

You can request that the frequency of pump-out events be changed or reassessed by the Water Corporation. However, there is a fee for the assessment, and it involves a series of inspections of the wastewater system to determine the system’s utilization. Keep in mind that a re-evaluation may also require you to pump the trap more frequently.

Maintain Your Grease Trap

If you suspect your grease trap requires maintenance, contact a commercial plumber asap.

How to keep your grease trap maintenance free by following the recommended guidelines set out by the manufacturers

Grease trap common sense!

  • Flush your kitchen drains regularly with hot water to help the solids move down the pipes into the grease trap.
  • Use environmentally friendly cleaners to keep the wastewater out of our sewer system. 
  • Everyone on your kitchen team should know how important it is to maintain your kitchen drains that drain into the grease trap. Help them recognize the signs that a grease trap needs cleaning so your plumber can take action as soon as possible if there are signs of trouble. 


Plumbmaster’s plumbers are the experts in installing, draining and troubleshooting grease traps for all retail and commercial businesses. We can advise and assist you with all aspects of replacing your old grease trap with a new one, from selecting the most appropriate grease trap for your needs to any additional installation work required for the new system, such as piping.

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