Grease Trap Installation and Maintenance

Grease Trap Perth (also called grease interceptors) reduce the amount of fats, oils and greases (FOGS) that enter sanitary sewer lines. They are often required in restaurants and require regular expert cleaning services.

Depending on your needs, you can choose between passive or automatic systems. These automatic systems reheat and remove FOG according to a programmed schedule, eliminating the need for manual pumping.

A grease trap (also known as a grease interceptor) is a plumbing device installed in your kitchen to prevent harmful fats, oils, and grease from entering the sewer system when it goes down sink drains. While they can be used in residences, they are typically found in commercial kitchens and restaurants where a high volume of cooking oil and food waste is generated.

Grease traps work by slowing down the water flow as it moves through the interceptor, allowing fats and oils to cool and solidify while the rest of the wastewater continues on its way into the drain and sewer systems. The FOG then floats to the top of the trap because of its lighter density, leaving the cleaner wastewater to continue on its way.

Because of this, the septic or sewer system is protected from the FOG that would otherwise cause costly blockages in drain lines. The longer you go between cleanings, however, the more grease builds up and hardens in your trap, making it less effective. This is why a regular maintenance schedule is important for your trap and should include both inspections and cleaning.

The traditional grease trap is buried outside and involves digging a large hole, laying in the pipe, and pouring concrete around it to hold it in place. An alternative is the passive hydromechanical, where the trap is built into a sink or other area in your kitchen.

Another option is the automatic grease removal unit, where the trap uses the same principles as a passive trap but has more pipes that pull the FOG away on its own on a programmed schedule. These units are much more efficient than passive traps and are often cheaper to operate in the long run.

The most efficient way to keep your trap operating at its peak is by sizing it according to your actual waste flow. To do this, you’ll need to know the size of your waste pipes as well as the type and rated capacity of your grease trap/grease interceptor. Many manufacturers have charts available listing the GPM flow based on pipe size, and all you need to do is add up all of the DFU values for your fixtures draining into the interceptor. This will give you the fixture’s total capacity in cubic inches, which can be converted to gallons by dividing by 231 (1 gallon = 231 cubic inches).


The grease trap (also known as a grease interceptor) is a vital component of food service drainage systems. It separates fatty acids, oils and greases from wastewater, so they don’t enter the main sewer system where they can cause blockages and foul odours.

FOG-rich waste from kitchen sinks, appliances and fryers flows through the drain and into a grease trap, where it cools and solidifies. This makes it heavier than water and buoyant, so it rises to the surface where it is trapped by baffles or a cover.

As the FOG layer accumulates, wastewater flowing through the trap slows down. This allows more time for separation as the less dense fatty substances rise and flow into a container, allowing solids to settle at the bottom of the trap. The resulting separation is known as passive hydromechanical grease trapping.

Stainless steel is the most popular material for grease traps due to its durability and resistance to corrosion in harsh kitchen environments. However, PVC and polypropylene are also common options for a variety of reasons, including being lightweight and cost-effective. They are good alternatives for outdoor grease traps, as well as in places where weight is an issue.

The most important consideration when choosing the best material for a grease trap is its strength and durability, especially when subjected to repeated high temperatures. Stainless steel is a top choice for heavy-duty applications, while plastics offer more versatility and are able to withstand a range of temperatures.

Another crucial factor is how frequently the trap needs to be emptied and cleaned. Some jurisdictions require grease traps to be pumped out at least once every month, and more frequently for high-volume restaurants. Failing to follow these guidelines can result in blockages and costly repairs.

The frequency of cleaning depends on the size and volume of wastewater passing through the grease trap, but should never be allowed to reach 25 percent capacity. Most manufacturers recommend that a restaurant owner clean their grease traps or have them professionally pumped out on a regular basis to ensure compliance with regulations and avoid unnecessary costs.


Whether you’re a restaurant owner or operate a commercial kitchen, a grease trap is an essential safety measure. These tanks separate fats, oils and grease (FOG) from kitchen wastewater so they don’t make their way into your pipes and the sewer system. But installing a grease trap isn’t as simple as digging a hole and connecting the inlet and outlet pipes. A professional plumber needs to install the trap, making sure it’s properly sized and connected to the inlet and drain pipes. And a plumber must know how to install the vents, which are used to ensure the trap doesn’t fill with fumes or block the flow of wastewater.

A residential grease trap is usually placed beneath sinks or in the basement of a home with multiple kitchen drains. A larger commercial trap may be installed outdoors in a designated area. But for both types of grease traps, the installation process requires a lot of work. First, a plumbing company must dig and prepare the ground for the trap. Then the trap is set in place, along with a screened lid. The inlet pipe and the outlet drain are then connected to the pipe leading to the sewer line.

Both residential and commercial traps must be sized based on the facility’s FOG volume and waste output. The traps should also be inspected regularly by a licensed plumber to ensure they are working properly and are free of debris.

A professional plumber can help you decide what size and type of grease trap is right for your kitchen, based on your FOG output and wastewater level. The plumber can also ensure the trap is pumped and cleaned at the appropriate intervals to avoid clogs, overflows and foul odors.

You can prevent the need for costly repairs and cleanouts by avoiding dumping food waste down your drains. Scrape solids off dishes before placing them in the garbage and never pour grease down the drain. Pouring excess cooking oil down the drain can solidify and cause clogs and backups in your kitchen plumbing, as well as in the city sewer lines.


It’s important to have regular maintenance performed on grease traps to keep them functioning properly. Failing to have them emptied and cleaned can result in blockages, pest infestations, foul odors, and potentially fines from your council if the grease overflows into nearby homes or businesses. During professional maintenance, your trap will be emptied and cleaned, then also tested to ensure it is working as it should be.

When cleaning your trap, you should always start by removing the thick layer of solid grease that has built up on the top. This should be done with a scoop and placed into a waste receptacle. Next, scrape the walls and baffles of the trap using a steel pot scrubber to remove any adhered grease build-up thoroughly. Once this is complete, use a shop vacuum to suck up the loosened grease residue inside the trap. After completing this step, flush the trap with clean water to wash away any soap and residue.

Aside from cleaning the trap regularly, you can prevent the build-up of grease and food waste by educating your staff on proper draining practices. Encourage them to scrape their plates and cooking utensils before placing them into the sink, as this will help to reduce the amount of FOG and solid food waste that enters the drain lines.

You should also avoid pouring chemicals, enzymes, or bleach down your trap to ‘clean’ it; this can kill the beneficial bacteria that live in the trap and cause the FOG to deliquesce into sludge, which then flows into the wastewater system where it causes blocked drains.

Grease traps are a vital piece of equipment in any commercial kitchen, keeping FOG and other contaminants out of sewer lines where they can cause costly problems for your business. With the right care, your grease trap will serve your establishment for years to come. However, if you notice signs of trouble, don’t hesitate to contact the experts at Wind River Environmental for a consultation and service of your grease traps. We will ensure that your traps are cleaned, tested, and in good working order to protect your business and the environment.