Gullies

Gullies are used as a method of collecting surface water to discharge to a drain. Gullies can be either untrapped or trapped. A trapped gully holds water to prevent foul air from escaping from the drain. They are used when discharging surface water into a foul drain. In some cases grey water (i.e. from ground floor bathrooms, utility rooms and kitchens) is also discharged into a gully from the waste pipe into the foul drain. If an untrapped gully hopper is used (sometimes necessary due to space restriction), it must be trapped using a UG42 or UG44 before entering the drainage system.

An untrapped gully can also be used if it is taking surface water, from a rainwater pipe or area of paving for example, into a surface water drain.

Note: If you are installing a new soil stack or drainage system, or significantly altering an existing system, you will need to inform the Building Control Department at your local Council. You will need to demonstrate that the work carried out conforms to Building Regulations: England & Wales or Scotland