What is a Gully Trap in Plumbing and Do You Need to Install One?

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Drainage systems are complex frameworks that cover not only the needs of removing wastewater from the home but also the prevention of dangerous sewage from underground drainage from backing up and releasing dangerous gases and foul air back into the home.

What is a gully trap in plumbing? One of the primary types of drainage structures in homes is the gully trap. A Gully Trap is a drainage pipe extension in the form of a basin that allows waste water to safely enter the sewage system with a seal that traps dangerous gases and prevents the gases from escaping.

Gully traps can best be thought of as the bridge between escaping water from the home and the barrier that allows this waste to connect to the underground drainage system. Every house needs to have one and it is important to know about the different types of gully traps and what they are used for. Read on to find out more.

Do I Need a Gully Trap?

It is crucial to have a gully trap. The principal way in which a gully trap works is by having one end of the gully that connects to the sewage outlet pipe from the home, a small reservoir at the bottom of the trap, and an exit pipe that takes the water into the sewage system.

Gully traps are needed to prevent the escape of dangerous gases that can form from waste and stagnant water, as well as to serve as a barrier to keep pests like rats and cockroaches from entering the pipe that leads into the home. A drainage gully can also work as an effective tool to remove rain and surface water.

The structure that keeps the gases trapped inside of the trap is known as a water seal, and this is a way of referring to the pool of water at the bottom of the body of the gully that prevents the gases from being able to escape through hoppers or the top seal of the gully trap. You can typically find a gully trap outside the home and near the kitchen or the bathroom from the outside.

What Is the Difference Between a Gully and a Drain?

The difference between a gully and a drain is that gully traps are used as barriers to not only connect the drainage system from the home but also to protect against toxins and pests. A drain is simply just that, a drain that takes waste water out of the home.

A drainage system needs a gully trap for proper delivery of waste to the underground drainage system, and can also remove rainwater from paved areas near the gully trap as well. Rather you have a p-trap or bottle gully (more on this below), blockages can sometimes occur, therefore, it is important to understand how much rainwater normally collects in your area to determine if you will need a gully trap that can be easily cleaned or not.

P Traps and Bottle Gully

Different Types of Gullies: P Traps and Bottle Gully’s

The two types of gullies are the p-trap gullies and the bottle gullies and each has a different way of working to achieve the same goal. A p-trap gully uses a 110mm drainage pipe to connect to a hopper that allows the drainage pipe to flow the waste to a small basket of water at the bottom that traps the odours and then flushes the waste into the outlet pipe.

A disadvantage to p-trap gullies is the difficulties that can arise with removing hoppers to make roddable sifts of debris to remove a blockage. For this reason, bottle gullies are the more preferred type of gully trap. If you have a p-trap gully that becomes blocked, you will likely need to consult with a drainage specialist to have the blockage cleared as it is difficult to clear a blockage out of the p-shaped pipes that make up a p-trap gully.

What Is a Bottle Gully Used For?

A bottle gully trap works much in the same way as a p-trap except these types of gully traps are roddable and do not require removable hoppers. The bottle gully is ideal because this type of gully does not trap water in a bottom basin, instead, bottle gullies rely on a sleeve inside the lining of the gully that forces the entering water up into the sewage pipes.

Water is still present inside of the bottle gully, but this type of gully is designed to be easier for cleaning if a blockage occurs. A bottle trap gully works by utilising an inner sleeve inside of the structure that can easily be removed for cleaning.

What Is a Back Inlet Gully Trap?

The back inlet variety is a bottle gully that is almost exclusively designed to provide all the normal benefits of a bottle gully with the added benefit of effectively removing large amounts of rainwater. Once rainwater enters the hopper, this can sometimes cause flooding with a regular bottle gully since the inlet pipe is not as high as the outlet pipe, which is addressed with a back inlet trap.

This type of gully is highly recommended if you have large accumulations of surface water that frequently cause flooding in the area near the gully trap.

How Do You Unblock a Gully Trap?

Trying to unblock a p-trap gully is difficult due to the curvature of the structure that prevents access into the entirety of the pipe. In order to get a blockage completely flushed out of a p-trap gully, it would take specialised equipment that is beyond the reach of DIY plumbing work.

With bottle gullies, clearing out a blockage is a bit easier since you can take out the inner sleeve and remove whatever debris is causing the blockage. This can occur more often from surface water that drains into the gully, specifically dirt and sediment that can build up over time.

Additionally, a drainage rod can easily be inserted into a bottle gully due to the greater access opened up based on the bottle shape of the trap. But this is not always the case, and other services available from drainage professionals may be required to move stubborn blockages.

Drain jetting is one type of service that can clear blocked drains due to the flexibility of the jetting hose, which can contour to a wide range of corners and tight spaces, as opposed to bulkier equipment. It takes an adequate amount of experience to effectively navigate the jetting hose, therefore a CCTV drain survey is also beneficial during the jetting process to have an effective visual guide for the process.

Contact KJC for Gully Trap Installation or Unblocking

Are you experiencing problems with a blocked gully trap or trying to determine if your property is properly equipped with gully traps or you need help with installation? KJC Drainage is fully-equipped to assist with any matters related to gully trap blockages or installation. Our team of professionals can also recommend other services for severe blockages.

We are a drainage company servicing Portsmouth and surrounding areas with over 20 years of drainage service experience. We can assess your property to determine where your waste water or surface water is draining to and check your existing gully traps to make sure the traps are working properly and effectively removing the waste and preventing dangerous odours from escaping.

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