The pipe has lost its fall
Drainage runs on gravity. A pipe needs a steady fall so that water carries solids along with it. If part of the run has settled, often where the ground was made up or where a driveway was laid over the top, water sits in the dip and solids drop out of suspension. You get a blockage in the same place every time.
Nothing you pour down the drain will fix a fall problem. It needs either a repair to that section or, where the dip is slight, regular jetting to keep it clear.
Fat, grease and soap build-up
This is the most common cause in kitchens and in any commercial premises that cooks. Warm fat goes down as liquid, cools in the pipe and hardens on the wall. Over months the bore narrows until the smallest bit of waste bridges it.
Rodding punches a hole through a fat layer and the water runs again for a while. High-pressure jetting is what actually strips the wall back to full bore, which is why we jet rather than rod when fat is involved.
Root ingress
Roots find the tiny amount of moisture escaping from a cracked pipe or an open joint and grow in through the gap. Once inside they form a mat that catches paper and wipes. Cutting them out restores flow, but the roots come back unless the defect they entered through is repaired or lined.
Displaced joints, cracks and partial collapse
Older clay pipework moves. A joint that has dropped even a few millimetres leaves a lip inside the pipe, and every bit of waste catches on it. A partially collapsed section does the same on a larger scale. Both cause repeat blockages at a fixed point in the run.
Wipes, sanitary items and the wrong things going down
Wet wipes do not break down, whatever the packet says. In a healthy pipe they usually pass. In a pipe with a lip, a dip or a root mat they are the thing that finally stops it. If the drain is already imperfect, wipes will find the fault every time.
How to work out which one it is
- Same spot every time, weeks apart: suspect a structural defect or a dip.
- Kitchen waste slow and smelly: suspect fat build-up.
- Problem worse after heavy rain: suspect a partial collapse or a surcharging shared sewer.
- Gurgling from a toilet or shower when another appliance drains: suspect a restriction further down the run.
- Ground sinking, damp patches or a sunken slab above the line: suspect a collapse.
When a CCTV survey pays for itself
Once you have paid for two or three clearances at the same drain, a survey is cheaper than continuing to guess. The camera shows the defect, its distance from the chamber and its depth, which means any repair is targeted rather than exploratory. We record the run and give you the footage and a report.
Questions we get asked
Will drain cleaner chemicals stop a drain blocking repeatedly?
No. Caustic products can shift a light soap or hair blockage in a waste trap, but they do nothing for fat coating a pipe wall, roots or a structural defect, and they do not reach the underground run in any useful concentration.
How often should a drain need clearing?
A sound domestic drain used normally should not need clearing at all. A busy commercial kitchen may need planned jetting every three to six months, which is maintenance rather than a fault.
Can you tell me the cause on the day?
Usually yes. We carry the camera with us, so once the run is clear we can inspect it there and then and tell you whether it was a one-off or a defect that will keep catching.