A drain that keeps blocking has either a build-up problem, fat, wipes, hair or scale collecting faster than the flow can shift them, or a pipe problem, a defect such as roots, a displaced joint or a sunken section snagging debris every time. Clearing the blockage treats the symptom. The permanent fix is a proper jetting clean plus a CCTV survey to find what the debris keeps catching on, then fixing that once.
Anyone can put up with one blocked drain. It is the third one in a year, in the same spot, that wears you down, along with the sense that you are paying again and again for the same job. The good news is that recurring blockages are rarely random. There is a reason the drain keeps failing, it is almost always one of the nine below, and each has a permanent fix.
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Build-up problem or pipe problem?
Every recurring blockage falls into one of two camps, and telling them apart is the whole game. A build-up problem means the pipe itself is sound, but what goes down it accumulates faster than the flow carries it away. Change the inputs, give the pipe a proper clean, and the problem ends. A pipe problem means there is a physical defect in the drain, and debris snags on it no matter how careful the household is. No amount of good behaviour fixes a displaced joint.
The clue is in the pattern. Blockages that follow behaviour, worse after big cooking sessions, better when the house is empty, point to build-up. Blockages that return to the same spot on a schedule of their own, whatever goes down the drain, point to the pipe. Keep that distinction in mind as you go through the causes.
The 9 causes of recurring blockages
1. Fat, oil and grease
The classic. Warm fat pours as a liquid, cools inside the pipe and sets on the walls, narrowing the bore a little more with every wash-up. Eventually the remaining channel closes. The permanent fix is twofold: a high pressure clean to strip the pipe back to bare bore, and a change at the sink, with fat going into a container and then the bin, never down the plughole.
2. Wet wipes and sanitary items
Wipes, including the ones sold as flushable, do not break down like toilet paper. They snag, mat together and bind with fat into solid masses, and water companies consistently name them among the leading causes of sewer blockages. Cotton pads, sanitary products and nappies do the same. The fix costs nothing: only pee, poo and paper go down the toilet, everything else goes in the bin.
3. Hair and soap scum
Bathroom drains block slowly and repeatedly as hair binds with soap residue into dense mats, usually in the trap or the first bend. A simple hair catcher over the plughole, emptied weekly, prevents most of it, and a proper clean of the affected run clears what has already built up.
4. Food waste and coffee grounds
Rice and pasta swell in water, coffee grounds settle like sediment, and peelings jam in traps. Kitchens that treat the sink as a second bin get blockages on repeat. Scrape plates into the bin and use a sink strainer, and this cause disappears.
5. Tree roots
Roots find their way into drains through joints and cracks, drawn by moisture, and older clay pipe runs in mature gardens are especially vulnerable. Cut them out and they regrow from the same entry point, which is why root blockages recur so reliably. The permanent fix is cutting the roots, then sealing the way in, usually with a liner or patch over the entry point.
6. Scale and silt
Mineral scale builds where water stands, and silt washes in from gullies, yards and downpipes, settling in slow sections of pipe. Both narrow the bore gradually until routine debris tips it over the edge. Jetting removes the deposit; dealing with why it settles there, often a flow or gradient issue, stops it returning.
7. Displaced joints and cracks
Ground movement, traffic above and simple age can shift pipe sections out of line or crack them. The resulting ledge or rough edge snags everything that passes. This is the signature cause of a blockage that always returns to the same place, and it only shows up on camera. The fix is a targeted repair of the defect, lined from inside where possible.
8. A sunken or back-falling section
Drains rely on a steady downhill gradient. Where a section has sunk (engineers call it a belly) or the fall was never right, water stands in the low spot and solids drop out of suspension there, seeding blockage after blockage. Clearing helps briefly; the lasting fix is correcting the low section, which is a job for a drain repair rather than another clear.
9. Early-stage collapse
The most serious of the nine. A pipe that is deforming or beginning to cave in narrows the bore and catches debris, and the blockages get closer together as the damage progresses. Recurring blockages plus bad smells, damp ground or a dip in the lawn above the run mean the pipe needs looking at promptly, before a partial failure becomes a full one.
How to find out which one you have
Start with the pattern, then confirm it with evidence rather than guesswork.
| What you notice | Most likely camp | Sensible next step |
|---|---|---|
| Kitchen drain, worse after cooking, greasy gully | Build-up (fat and food) | Professional clean, then change what goes down the sink |
| Toilet blocks repeatedly, wipes used in the house | Build-up (wipes) | Clear it, bin the wipes, see if it holds |
| Same spot every time, regardless of behaviour | Pipe defect | CCTV survey to find the snag |
| Recurs near a tree, clears never last long | Roots | CCTV survey, root cut, seal the entry |
| Blockages plus smells, damp or a sinking lawn | Possible collapse | Survey promptly, do not keep re-clearing |
The confirming step for anything in the pipe-defect camp is a CCTV drain survey. The camera travels the full run, records the condition of the pipe and pinpoints any defect to within centimetres, so a repair fixes the exact spot rather than an educated guess. If the survey finds nothing wrong, that is money well spent too: it rules out the pipe and tells you the answer lies in habits and cleaning.
If the drain is blocked right now, deal with that first. Our drain unblocking service clears most drains the same day with drain jetting, and because the camera and the jetter travel on the same van, a recurring blockage can be cleared and surveyed in one visit.
Stopping it happening again
Once the cause is fixed, keeping the drain clear is mostly routine. Watch what goes down the kitchen sink, keep wipes out of the toilet, fit hair catchers in the bathroom, and clear leaves and silt from outside gullies each autumn, a job that matters in leafy parts of Devon and Cornwall more than most. For drains with a history, busy households, or holiday lets that cannot afford a blockage in changeover week, a scheduled drain cleaning visit once or twice a year keeps the pipe ahead of trouble for less than the cost of a single emergency callout.
Frequently asked questions
Why does my drain keep blocking in the same place?
A blockage that returns to the same spot almost always means something in the pipe is catching debris: a displaced joint, a crack, root intrusion, a sunken section holding standing water, or hardened scale. Clearing the blockage removes the symptom but not the snag. A CCTV survey shows exactly what the debris is catching on so it can be fixed once.
Why do my drains keep blocking every few months?
Regular re-blocking is either a build-up problem, usually fat, wipes, hair or scale accumulating faster than the flow can shift it, or a pipe problem, where a defect snags debris. If the drain serves a kitchen or a busy bathroom, habits and a proper jetting clean often solve it. If it recurs regardless of what goes down it, the pipe needs inspecting.
Can wet wipes really block a drain even if they say flushable?
Yes. Wipes marketed as flushable still do not break down the way toilet paper does. They snag on any rough spot or joint, mat together and bind with fat into solid masses. Water companies consistently name wipes among the leading causes of sewer blockages. Bin them, even the flushable ones.
How do I know if tree roots are blocking my drain?
Suspect roots when blockages recur near a tree or large shrub, particularly on older clay pipe runs, and when clears do not hold for long. Roots enter through joints and cracks seeking water, then regrow after every cutting. Only a camera survey confirms them, and the permanent fix is cutting the roots out and sealing the entry point.
When should I get a CCTV survey for a recurring blockage?
After the second blockage in the same drain within a year, or the first if it comes with warning signs such as bad smells, damp ground or slow drainage everywhere. A survey costs a fraction of repeated callouts and identifies the actual cause, or rules the pipe out so you can fix the habits instead.
Tired of clearing the same drain?
We clear the blockage and find out why it keeps coming back, in one visit where possible. Jetting, camera surveys and honest answers across Plymouth, south east Cornwall and south and west Devon.
Call DCI Drainage on 07418 000 420 Fast, free quotes · hello@dcidrainage.co.uk
