Drain keeps blocking? Why it happens and the real fix
When a drain keeps blocking, the blockage is the symptom and something else is the cause. A sound drain run has enough fall and a smooth enough bore that ordinary waste simply does not stop in it. So a run that blocks for the second or third time is telling you there is a point where things can catch, and until that point is found, every clear is temporary.
Why blockages come back
Fat and wipes often work together. Grease goes down hot and liquid, cools inside the pipe and sets on the walls. Wipes, even the ones sold as flushable, do not break down the way paper does, and they snag on the greasy patches. Each layer makes the bore narrower and the next snag easier.
Scale builds on the inside of older cast iron and clay pipes, especially with London’s hard water. A scaled pipe has a rough, narrowed bore that catches paper and debris that would sail through a clean one.
A defect in the pipe itself is the cause that jetting can never fix. A partially collapsed section, a displaced joint, a length that has sagged into a belly holding standing water, or tree roots that have found their way in through a joint: all of these create a permanent catching point. Roots in particular regrow after cutting, so they come back on a schedule.
In a block of flats, the cause may not be yours
Where flats share a soil stack or a communal run, the lowest point shows the symptom while the cause sits upstream. The ground floor gully that overflows every few months may be perfectly clean itself, fed by fat from a kitchen three floors up. This is why recurring blockages in the same stack are a building problem rather than a flat problem, and the run needs surveying as a whole. Neos Engineering handles communal drainage for block managers and property management companies across all of London.
What is worth doing yourself
A plunger, cleaning the trap under a slow sink, and lifting the grid on an outside gully to clear leaves are all sensible. So is keeping fat, oil and wipes out of the drain entirely, with a fat trap or jar in the kitchen.
Caustic drain chemicals poured down on repeat rarely shift a real blockage and they attack older pipework. And if more than one fixture is slow at once, the problem is past the traps and into the run, where household tools do not reach.
Why repeat clears are the expensive option
A one off clear treats the symptom. The jet cuts a hole through the fat or pushes the wipes along, everything flows, and the scale, root or defect that caused the catch is still there. So the drain blocks again in weeks or months, and each repeat brings another call out and another round of risk to floors and ceilings if it surfaces indoors. Over a year, paying to find the cause once is usually the smaller bill than clearing the same run on a loop.
What a proper investigation involves
The run is cleared first, then a CCTV camera goes through it. The survey shows what the cause actually is and locates it precisely, including its depth. The remedy is then matched to the fault: descaling for scaled pipe, a root cut and a patch liner where roots are entering, a liner or targeted repair for a displaced joint, and excavation only when a section has collapsed. Neos Engineering clears blocked drains and traces blockages that keep coming back, and any further work is quoted before it goes ahead.
When to call rather than persist
Call when the same run has blocked more than twice, when several fixtures slow down or gurgle together, when a gully or manhole is overflowing, or when there is any sewage backing up indoors. The call out service runs 24 hours a day, 365 days a year.
What actually stops it
A drain that keeps blocking has a cause, and it is one of a short list: fat and wipes, scale, roots, a damaged pipe, or a shared run with a problem upstream. A camera survey finds which one, a targeted fix ends the cycle, and that is nearly always cheaper than meeting the same blockage every few months.
If you need us
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Call any hour, email us, or get a price in under a minute. The hourly rate is confirmed when you book. A call out is charged by the hour, and a return visit or further work is quoted first.