What is a Gully Trap in Plumbing and Do You Need to Install One? (2024)

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 co*ckroaches 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.

What is a Gully Trap in Plumbing and Do You Need to Install One? (1)

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 Portsmouthand 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.

What is a Gully Trap in Plumbing and Do You Need to Install One? (2024)

FAQs

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

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.

What is a gully trap? ›

A gully trap is a basin in the ground which receives piped wastewater from inside your home before it is emptied into the wastewater network. The basin has a water seal to prevent foul odours of the sewer reaching the surface, and a vent pipe that allows fresh air in.

What is the purpose of gully? ›

Domestic Drainage Gullies

Domestic gullies are designed to discharge surface water from your garden, rainwater from your guttering, and grey wastewater from your washing machine, dishwasher, bath, shower and sink into the appropriate drains.

Where is gully trap used? ›

All houses have at least one gully trap against an outside wall, usually next to the kitchen, bathroom or laundry. Gully traps should be raised off the ground. This will prevent groundwater from entering our wastewater network, and reduce the chance of overflows.

How do you install a gully trap? ›

How to install a Bottle Gully - OsmaDrain - YouTube

Why do you need gully traps? ›

A gully trap is provided outside the building before connecting to external sewerage line. It also collects waste water from the kitchen sink, wash basins, baths and wash area. Gully Trap is provided to prevent the foul gases entering in to the building by providing water seal.

What does a gully look like? ›

Gullies resemble large ditches or small valleys, but are metres to tens of metres in depth and width and are characterised by a distinct 'headscarp' or 'headwall' and progress by headward (i.e. upstream) erosion.

What is the minimum depth of water required in gully trap? ›

What is the minimum depth of water required in gully trap? Explanation: Gully traps are deep seal traps, the depth of water seal should be 50 mm minimum. It prevents the entry of insects from sewer line to waste pipes carrying wastewater.

Why is it called gully trap? ›

In fact, its name describes its purpose. A gully is a drainage system designed to control surface water, usually rain, and a gully trap is designed to 'trap' smells and gases inside the drainage system. There are two main types of gully traps – the P trap gully and the bottle gully.

What is the difference between a gully and a drain? ›

A drain gully, or gully traps or gullies as they're often called, are drains that catch surface water like rainwater and grey waste (wastewater from your dishwasher, washing machine, shower, etc.).

What is the drain outside the house called? ›

Gutter Drainage

A gutter and downspout system helps drain all roof water away from your home's walls. The downspout drain should extend beyond the walls and direct the water to a storm sewer or catch basin.

What is the most important part of a trap? ›

The most important element of your trap beat might just be your kick drum and 808 pattern. Your kick and 808 are what give your trap that heavy, trunk-rattling bass. Putting your kick or 808 on beat 1 is essential, but beyond that, you're on your own.

What is a gully on a house? ›

What is a gully? A gully is like a basin that's usually positioned under a road with a drain gate sitting above it. Water collects in the gully before joining the main sewage network. To ensure that water can flow freely, it's important to make sure that gullies are kept clear with regular inspections.

Why is it called gully trap? ›

In fact, its name describes its purpose. A gully is a drainage system designed to control surface water, usually rain, and a gully trap is designed to 'trap' smells and gases inside the drainage system. There are two main types of gully traps – the P trap gully and the bottle gully.

What is the difference between gully trap and manhole? ›

Basically, a gully trap is used to when a pipe carrying waste water is connected to an external manhole. It invariably carries waste water from a bath or a sink and has a bent pipe with a water seal, so that foul gases from the sewage line does not enter the room.

How do you unblock a gully trap? ›

If you forget to do this...be prepared to potentially get a bit wet...and probably smelly too.
  1. Step 1 - Locate the gully. ...
  2. Step 2 - Remove the gully trap/grid. ...
  3. Step 3 - Check inside the gully. ...
  4. Step 4 - Use a drain Rod. ...
  5. Step 5 - Rinse out the gully. ...
  6. Step 6 - Flush out the gully. ...
  7. Step 7 - Test the gully.
Feb 8, 2021

Why does Australia have boundary traps? ›

They are there to prevent the build-up of harmful sewer gasses which can accumulate within the drains of residential properties and are required by water services providers; however, it is the responsibility of a licensed plumber to determine the 'boundary trap area' (usually quite close to the main sewerage line).

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