In short
Start by clearing any leaves or silt from the gully cover. If the run beyond it is reachable, try a drain rod on the blockage. If the water still will not drain, or the problem returns, high-pressure jetting cleans the pipe wall properly.
A repeat problem after jetting needs a CCTV survey, because another round of jetting will not fix the cause. You can send a request online for any of these.
Recognising the signs
Standing water in a gully or inspection chamber is usually the first sign. You may also notice a smell from the cover, or water backing up when the washing machine empties. In older Banbury terraces such as Grimsbury and Neithrop, clay pipes laid decades ago can crack or shift. As a result, silt and debris have somewhere to collect.
Autumn makes it worse because leaves from trees along the Cherwell and the canal wash into gullies. Check any of these signs early, before a small problem grows.
What to try yourself first
For a surface blockage, you can often make progress without special kit, because most gully covers lift easily. Lift the gully cover with a lever or screwdriver. Clear away loose leaves, twigs and grit by hand or with a garden trowel.
If the channel beyond is shallow, work a standard drain rod gently back and forth. Pull it out now and then to remove what it dislodges. These steps are worth trying, but they still have limits. A rod tends to punch a hole through a blockage, so grease and root fragments stay behind and the blockage returns within days.
Roots in a joint or a collapsed clay pipe will only get temporary relief from rodding, because the cause stays. Our external drain unblocking service covers the next step.
When jetting is the right call
Jetting uses a pump to send a focused jet of water through a flexible hose. The pressure is far beyond a garden hose or a pressure washer, while a rod only pushes. Unlike a rod, the jet scours the whole inside of the pipe.
It removes silt, grease and biofilm, and it cuts through fine roots in the joints. If your own attempts have not cleared the water, jetting is the logical next step. It also leaves a clean pipe wall, which gives a far clearer picture if a CCTV inspection follows. Our drain jetting service page has more detail, and our guide to jetting and rodding compared compares the two methods.
When a CCTV survey is the answer
A CCTV survey feeds a camera along the pipe to record its real condition. Book one when blockages keep coming back despite jetting. That pattern therefore points to a crack, a misaligned joint or a partial collapse.
It also helps when you suspect roots but need proof. A survey is useful before you choose between repair and replacement, because it shows the length, size and state of the pipe. Engineers usually grade defects with the WRc MSCC5 scheme, so you and any contractor share one clear basis. Our CCTV drain survey service explains the process, and our piece on what a survey costs covers the price factors.
Local factors around Banbury
Much of Banbury's older housing, particularly the late Victorian and Edwardian terraces around Grimsbury and Neithrop, uses clay drains. They last well, yet they can turn brittle with age. Ground movement and root pressure then crack them more easily.
The town sits close to the Cherwell and the canal, so many gardens have mature trees. Roots seek out the moisture in a drain, especially while the autumn is wet. Leaf fall from street trees and shrubs is a recurring cause of the surface blockages that send people looking for help.
If your home is off the mains, the Environment Agency's General Binding Rules apply to any discharge. Work on a tank or soakaway also has to meet Building Regulations. Tanker emptying needs a licensed waste carrier, and our work covers installation, repair and assessment instead.
Help near you
Outside drains are our everyday work. For houses in Brackley, see drain unblocking in Brackley. On the Cotswold edge, try outside drain clearing in Chipping Norton. We also cover drain jetting in Kidlington and blocked drain help in Woodstock.
If you are not sure whose drain it is, read first. The Thames Water responsibility guide explains where private ends and public begins.
Related guides
Gullies and manholes often fail because of a wider problem, so check the common signs of a failing drain. Kitchen waste is a common cause, which is why preventing kitchen drain blockages matters. A blocked toilet alongside a flooded gully points to the main run, as covered in unblocking a toilet step by step.
Frequently asked questions
Can I unblock an outside drain myself?
You can safely clear surface debris and try a drain rod on an accessible run. If the water still will not drain, or the problem returns fast, the cause is deeper. Roots, grease further down or a structural defect then call for jetting or a survey.
What is the difference between jetting and rodding?
Rodding pushes through an obstruction with a solid rod and often leaves residue behind. Jetting uses a high-pressure water jet to clean the full circle of the pipe. It removes silt, scale, grease and fine roots, not just a channel through the middle.
How much can I clear with a drain rod?
If the run is short and the blockage is near the surface, a rod often shifts it. However, if several passes bring no change, or water returns within a day or two, stop. Move to jetting or a survey instead of repeating a method that is not working.
Why do outside drains block in autumn?
Leaf fall is the main reason, because leaves, twigs and garden debris wash into open gullies in wet weather. Keeping the covers clear through October and November is one of the simplest ways to stop a blockage forming.
