An outside gully is the open drain with a grating, usually below a kitchen waste pipe, a bathroom waste or a rainwater downpipe. Because it is open, it collects grease, food, leaves, soil and silt. A blocked gully is one of the most common drainage problems, and one you can often fix yourself.
Signs your gully needs cleaning
- Water pooling around the grating, or overflowing when the sink or washing machine empties
- Bad smells near the back door
- Grease or a thick layer of debris visible under the grating
- The kitchen sink draining slowly
What you will need
- Thick rubber gloves, and eye protection if you have it
- A small trowel or old cup, or a gully scoop
- A bucket and a bin bag
- A hose or a bucket of water
- A stiff brush
How to clean it
- Stop using water in the sink, washing machine and dishwasher that drain to the gully.
- Lift the grating. Clean it with a brush.
- Scoop out the debris: leaves, silt, food and grease. Put it in a bin bag, not back down the drain.
- Clean the sides of the gully with the brush.
- Flush it through with a bucket of water or the hose. The water should drain away quickly.
- Refit the grating, and consider a leaf guard if a downpipe runs into it.
Avoid pouring boiling water or strong chemicals into a gully, and never mix drain products. See do chemical drain unblockers work?
If it still does not drain
If the gully is empty but water still will not go away, the blockage is in the pipe beyond the gully or in the underground drain. Check the nearest inspection chamber: if it is full, the blockage is further downstream. See how to find your drains and how to unblock a drain.
Why gullies block
- Fat and grease from kitchen sinks and dishwashers, which coats the gully and sets
- Food waste, including rice, coffee grounds and peelings
- Leaves and moss from gutters and downpipes
- Soil and silt washed in from paths and gardens
- Lint from washing machines
Keeping it clear
- Wipe greasy pans with kitchen roll before washing, and use a sink strainer.
- Check and clean the gully every few months, and in autumn.
- Fit a gully cover or leaf guard.
If your gully keeps blocking, grease may have built up along the drain. Professional drain cleaning or drain jetting clears it from the pipe walls. See also why does my sink keep blocking?