Drain gullies are a central part of a property’s drainage system, helping to prevent flooding and protect against damage caused by excess water.
If you’re wondering what a drain gully is and why you might need one, this guide covers everything you need to know, from installation tips, to cleaning and maintenance.
What is a drain gully?
A drain gully is a plumbing fixture that collects wastewater from sinks, showers, gutters and other sources before directing it into the underground drainage system. It acts as a barrier, trapping debris and preventing it from entering the main sewer system.
What does a gully look like?
Drain gullies often have a vertical pipe leading to an underground chamber. They typically include a removable cover, so you can inspect and clean the gully easily.
The chamber below is designed to trap debris, such as leaves, while allowing water to flow into the drainage system.
Why do you need a drain gully?
Drain gullies play a crucial role in managing wastewater and rainwater. Without them, debris could clog the drainage system, leading to blockages, flooding and expensive repairs.
Drain gullies also prevent unpleasant odours from escaping by maintaining a water trap that blocks sewer gases.
How deep is a drain gully?
The depth of a drain gully depends on its type and purpose, but it usually ranges from 300mm to 600mm. The gully’s depth should comply with building regulations, ensuring it’s effective and safe.
How to install a drain gully
Below is a step-by-step guide to installing a drain gully safely and correctly:
- Plan the location: Determine where the gully will collect water, such as near a downpipe or surface water outlet
- Dig out the area: Dig a hole large enough to fit the gully and its connections. Drainage gullies should be installed 150mm below the property’s damp proof course.
- Lay a base: Create a stable base using compacted gravel or concrete to support the gully.
- Connect the pipework: Attach the inlet pipes to the gully and ensure a secure, watertight fit.
- Install the gully: Place the gully chamber into the hole, ensuring its level and aligned properly with the drainage pipes.
- Backfill and secure: Fill around the gully with concrete or soil, leaving the cover or grating accessible for maintenance.
- Test the system: Run water through the gully to ensure adequate flow and no leaks.
How to clean a drain gully
Regular cleaning is essential to keeping your drain gully functioning correctly. Here are the steps we recommend for a thorough cleaning routine:
- Remove the cover: Carefully lift the gully cover
- Clear debris: Wear gloves and use a trowel to remove leaves and other debris.
- Flush the gully: Pour hot water into the gully to dissolve grease or soap residue.
- Check for blockages: Ensure the water flows freely into the drainage system.
- Replace the cover: Secure the cover back in place once cleaning is complete.
For more cleaning tips, check out our guide on how to clean your gutters.
How to clear a blocked drain gully
Blocked drain gullies can cause water to back up and lead to flooding. Follow the below steps to tackle a blockage:
- Inspect the blockage: Remove the cover and identify what’s causing the issue.
- Use a plunger: Apply a plunger to the drain to dislodge any obstructions.
- Deploy a drain rod: Push a drain rod into the gully to break up stubborn blockages.
- Flush the system: Pour water into the gully to confirm the blockage has cleared.
It’s best to hire a professional, especially for more complex blockages, as they will have the tools and expertise to clear it, safely.
For additional guidance, our guttering repair guide provides tips on dealing with common drainage issues.
The best type of drain gully
Choosing the right drain gully depends on your property’s requirements. Here are some common types:
- P trap gullies: These feature a water trap that prevents sewer gases from escaping, making them perfect for residential use.
- Bottle gullies: Compact and easy to maintain, bottle gullies are popular for tight spaces.
- Back inlet gullies: Designed for situations where the inlet pipe enters from the back, commonly used with surface water systems.
Check with a professional which type of gully is best for your property’s drainage system.
Drain gullies are a crucial component of any effective drainage system, ensuring water flows freely while preventing blockages and odours. Get in touch with our team today to learn more about our drainage and waste systems.