Blocked drain outside the house: what to do first

Water pooling round the grid outside the kitchen, a smell in the yard, or a manhole lid in the drive with dirty water lapping at the rim. Outside drains tend to block in late autumn, when leaves come down and heavy rain washes soil into every gully. The good news is that a few minutes with a torch tells you a great deal about where the blockage is and who should be dealing with it.

Right now: stop sending water down

Before anything else, tell everyone in the house not to flush, shower, run a bath or start the washing machine or dishwasher. Every litre that goes down a blocked drain has to come back up somewhere, and the lowest point is often a downstairs toilet or the shower tray. If dirty water has already come up inside, keep children and pets out of that room and wash your hands after touching anything it has reached.

Work out which drain you are looking at

Most houses across Greater Manchester and north Cheshire have three kinds of opening outside, and each one points to a different problem.

• A gully with a small grid, usually at the foot of a downpipe or under the kitchen waste pipe. If only this is full and everything inside still drains normally, the trap just below the grid is choked.
• An inspection chamber, the square or rectangular cover in the path, yard or drive. Lifting it shows you the channel your waste runs through.
• A road gully in the kerb. That one belongs to the highway authority, not to you; report a blocked one to your local council.

Lifting the cover: what it tells you

Use a screwdriver or a pair of old keys in the lifting slots, wear gloves, bend your knees, and slide the lid aside rather than trying to lift it high. Never leave the hole open and unattended.

• Chamber full of water: the blockage is downstream, between this chamber and the next one or the sewer.
• Chamber empty, but sinks and toilets inside are slow: the problem lies between the house and this chamber.
• Chamber flowing freely: the fault is probably in a single waste pipe indoors, not in the main drain at all.

In the long rows of terraces in Salford, Eccles, Oldham and Stockport, older homes often have an interceptor trap at the bottom of the last chamber, with a small stopper on a chain. When that stopper drops out it sits in the channel and catches everything that comes past, which is a very common cause of a full chamber in Victorian and Edwardian streets.

Is it yours, a neighbour’s or the water company’s?

This matters because it decides who pays. As Salford City Council explains, a drain is the pipe taking waste from one property and a sewer is the pipe serving more than one; once two drains join, that section becomes a public sewer. Since 2011 many pipes that used to be private sewers have been transferred to the water companies, and the council names United Utilities as responsible for repairing and maintaining public sewers in Salford.

So if your own chamber is empty but your neighbour’s is overflowing, or several houses in the row are backing up together, the blockage is probably in a shared section. Report it to the water company before paying anyone to clear it. If only your chamber is full and the next one along is empty, the blocked length is almost always on your side.

What not to do

• Do not pour chemical cleaner into a full gully or chamber. It will not shift leaves or silt, and it leaves caustic water for someone to reach into.
• Do not push garden hoses or makeshift rods hard into the outlet. They can lodge in the pipe or crack an old clay joint.
• Do not stand on a lifted lid or leave it propped across the hole.
• Do not keep running water “to see if it has cleared”; test it once, gently, from one tap.

When to call, and what happens next

Call 07893 933403 or send a WhatsApp photo of the open chamber when sewage is coming up inside, when the full chamber is clearly on your side, or when you have cleared a gully and it fills again within the hour.

We lift the covers along the run to find exactly which length is full, then clear it with drain rods or a machine from the nearest access point, working towards the blockage rather than pushing it further in. Once the water is moving, each fitting is run in turn to check it all drains away. If the cause looks like a sunken length, roots or a broken pipe rather than a one-off build-up, you are told what we found before anything else is done. Our blocked drains page has more on the work itself, and every other plumbing job we attend is on the main plumbing page.

You pay by the hour, not by the drain: £89 covers the first hour, any further time is £45 per half hour, there is no fee just for turning up, and the rate holds at 2am on a Sunday.

Keeping outside drains clear through the winter

• Clear leaves from yard gullies every week or two while the trees are bare, and fit a leaf guard on the gully grid if one is missing.
• Keep gutters and downpipe hoppers clear, because whatever collects in them washes straight into the gully. Our page on guttering and fascias covers repairs if a gutter is sagging or leaking.
• Bin wet wipes, cotton buds and nappies, even the ones sold as flushable.
• Wipe fat and oil out of pans with kitchen roll before washing up; it sets in cold outside pipes.
• Know where your inspection chambers are now, so you are not hunting for them in the dark with a torch.