Outside drain and gully unblocking

Water is standing over the grate outside the back door, or the gully in the yard is overflowing again. You want to know whether it is a ten-minute job or a real drain problem. Drainage Emergency clears outside drains, gullies and channels across Derby 24/7 by rodding or high-pressure jetting. We then flush the run through to confirm the flow is fully restored.

A blocked outside drain is usually a gully trap packed with leaves, silt or kitchen fat. Sometimes it is a blockage in the pipe run beyond it. This page explains which of the two you have, and what happens when an engineer arrives. It also covers whose pipe it is, and when it is worth trying yourself first.

Why an outside drain blocks

An outside drain blocks in one of two places. Either in the gully trap directly under the grate, or in the pipe run beyond it. The gully is the small chamber under the grid outside your kitchen or back door. It holds a plug of water (the trap), so sewer smells cannot come back up. Everything from the sink, washing machine and downpipes passes through it.

Leaves, moss and soil wash in from the top. Fat, food and washing-up grease arrive from the kitchen waste and set as they cool. Give it a year and the trap is a solid lump. Water pools over the grate.

The run beyond the gully is a different problem. Wipes and sanitary waste that came down the foul drain will hold everything behind them. So will a root that has found a joint in an old clay pipe. Water then backs up to the lowest point, which is usually that same outside grate. Same puddle, different job.

Is it the gully or the drain beyond it

Two quick checks tell you which one you have. Lift the grate and look. If the chamber is full of black silt, leaves and grease, the trap is choked. The water sits in it, and the pipe beyond is probably fine. If the chamber is clear but the water still will not drop, the blockage is further along.

The second check is your other drains. When only one gully is affected, the problem is local to it. Three signs point to the main run instead.

The toilet is slow as well. A manhole cover in the garden is lifting. Next door has water in their yard too.

Any of these means the main run is blocked, and the gully is only where it shows. Gurgling from plugholes indoors when the outside drain is full points the same way. Tell us which you are seeing when you call.

What we do when we arrive

The engineer starts at the gully. The trap is emptied by hand and the chamber cleaned out. Then the run is tested with water. If it still backs up, the engineer lifts the nearest inspection chamber downstream and works back with rods.

Where the blockage is fat, silt or roots that rods only push about, the engineer brings in the high-pressure jetting unit. Jetting cuts the deposit off the pipe wall and washes it down to the sewer. This is different from leaving a hole through it.

Before leaving, the run is flushed through and watched until the water clears. When the cause is not obvious, or the same drain has blocked before, a closed-circuit television (CCTV) camera goes down the pipe. It looks for the reason: a displaced joint, a root, or a belly, a sag in the pipe, holding silt.

You get told what was found and what, if anything, needs doing next. The follow-up, if there is one, is a CCTV drain survey. If that is the visit you need, ring 01332 215521.

Whose drain is it: yours, your neighbour’s or Severn Trent’s

The drain that serves only your property, inside your boundary, is yours to clear. Beyond the boundary, and for any run shared with a neighbour, the pipe became Severn Trent’s responsibility. This happened in the 2011 transfer of private sewers. That matters here.

Chaddesden’s 1930s to 1960s semis (DE21) have long back-garden runs to a rear gully. Mickleover (DE3) has shared drives where two or three houses feed one pipe. So the blocked outside drain in your yard may be sitting on somebody else’s pipe.

The gully itself, and the short length to the shared run, is nearly always yours. If we find the blockage is in Severn Trent’s section, we will say so. You can then put the call in to them rather than paying us to clear it. Highway gullies in the road belong to Derby City Council, as the Lead Local Flood Authority. They are not Severn Trent’s, and not yours.

Outside drains around Derby

Our office is on Mansfield Road (DE21), a few minutes from Chaddesden Park. So Chaddesden, Oakwood and Spondon get the quickest attendance. Chaddesden’s original clay drains and long garden runs are the classic gully-and-run combination.

Down in Alvaston (DE24), on the flat ground around Alvaston Park beside the Derwent, the drains have shallow falls. Silt and fat settle out instead of washing through. Jetting is the routine fix there, not rods. Across town in Mickleover, the shared drives on the newer estates make responsibility a live question on most visits.

Then there is the rain. Markeaton Brook runs from Markeaton Park in a culvert beneath the city centre and is historically Derby’s most destructive flood source. In a downpour the sewers and the culvert run full. A gully that was half silted all summer is the one that overflows.

One customer described their driveway drain blocking as heavy rain came in on a Saturday. Water started to rise inside the house. Our surface water drainage page covers rain-driven flooding in its own right.

Can you clear it yourself first

Often, yes. If the gully trap is full of leaves and silt, a pair of gloves, a bucket and a hose will clear it. Several customers have written that Chris talked them through exactly that over the phone without charging. A set of drain rods will shift a soft blockage a short way along the run. Always turn them clockwise so the sections do not unscrew in the pipe.

This stops being a DIY job if you see any of these.

• standing sewage
• a blockage that comes back within weeks
• water in more than one drain
• a suspected root or collapse
• any shared run

Rods driven hard into a cracked clay pipe make a repair job out of a clearing job. Chemical drain cleaners do nothing useful in a gully. They leave the engineer working in caustic water.

What to have ready when you call

Ring 01332 215521, any hour, any day of the year, and you will be asked four things. Which drain is affected, whether other drains or the toilet are slow, and whether the water is clean rainwater or foul. The engineer will also ask whether a manhole cover is lifting. That is enough for the engineer to load the right kit.

Quotes carry no hidden fees, and for work quoted below two thousand pounds you pay only on completion. We are insured with £5 million public liability cover. Customers regularly report us arriving within the hour. The reviews on this site also mention weekend and Saturday callouts to a pub and a retail shop, as well as homes.

If the blockage is inside the house, our blocked toilet and blocked sink pages cover those jobs. Our emergency drain unblocking page covers a main run that has stopped altogether.

If the grate is under water now, ring and tell us what you can see. The engineer arrives with rods, the jetting unit and a camera. They clear the gully or the run, and show you the water running away before leaving.