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Drainage advice
Straight answers about drains
Written for people in Bristol who have a problem and want to understand it before spending money on it. No jargon, no scare tactics, and a fair amount of advice that costs us work — because the alternative is worse.
MOST READ
Who is responsible for a blocked drain in Bristol?
Yours, Wessex Water’s, or the council’s — and how to tell which before anyone sends you an invoice. Covers shared drains, the 2011 sewer transfer that most online advice predates, rented homes, and converted flats.
Quick answers
What people actually ring us about
Short answers to the questions that come up most on the phone. If yours isn’t here, just call and ask — we don’t charge for answering questions.
My drain keeps blocking. Why won't it stay clear?
Because the blockage is being moved rather than removed, or because something in the pipe is still catching everything that passes — a fat line, roots through a joint, a cracked section, or a run laid at the wrong fall. Rodding punches a channel through; it doesn’t clean the pipe wall. If the same drain has blocked more than twice in the same place, another clearance is treating a symptom.
- How a survey finds the cause
What should I do while I'm waiting for someone to arrive?
Stop using water. Taps, toilets, dishwasher, washing machine — anything you send down has nowhere to go and adds to what comes back up. Don’t flush a high toilet again to test it, and don’t pour chemical cleaner down. If you already have, say so on arrival; caustic water in a trap is a genuine hazard for whoever opens it.
- Blocked drain clearance
Is the blockage inside the house or outside?
Lift the cover on the inspection chamber nearest the house. Empty means the blockage is between the house and that chamber — internal pipework. Full means it’s downstream, somewhere in the underground run. If you’d rather not lift covers, the pattern tells us most of it: one slow fixture is usually internal, while several affected fixtures or an overflowing outside drain is nearly always the main run.
- One fixture or several?
Do chemical drain cleaners work?
Rarely, on a real blockage. If the pipe is already full of standing water the cleaner never reaches the obstruction — it dilutes and sits there. It may soften the surface of a hair and soap mat but won’t dissolve one, and it does nothing to a hardened fat line. Repeated use can damage older pipework and trap seals, which matters in a city with as much Victorian plumbing as Bristol.
- What to try instead
Are flushable wipes actually flushable?
No, in any practical sense. There’s no UK standard behind the word. Wipes don’t break apart in water the way toilet paper does — they catch on a rough joint or a root and then collect everything that follows. They’re the single commonest cause of blocked toilets we attend. The safe list for a toilet is genuinely just three things: pee, poo and paper.
- What can and can't be flushed
Do I need a drain survey when buying a house?
A standard homebuyer or building survey does not inspect the drains, so unless you arrange one separately nobody looks. It’s most worth doing on period properties, anywhere with mature trees nearby, converted flats sharing a run, properties extended over the drain, or where there’s any sign of subsidence or damp. On a new-build under ten years old the warranty usually covers it.
- Homebuyer drain surveys
Will you have to dig up my garden to repair a drain?
Usually not. Cracks, fractures, root damage and displaced joints can nearly always be repaired from inside the pipe with a patch or a full liner, following the original route with nothing above ground disturbed. Excavation is a last resort for genuine collapses — and on those jobs, reinstating the driveway or patio is often the larger half of the bill.
- No-dig drain repairs
Rats keep coming back after pest control. Why?
Because baiting removes the rats that are there but doesn’t close the route they used. The sewer network has more, and they follow the same path. That route is almost always a drainage defect — a cracked pipe, a displaced joint, or an old branch left uncapped when a bathroom or outside toilet was removed. Treatment working and then stopping is itself the evidence.
- Finding the way in
Who writes this
All of it comes from jobs. Flow Sure Drains is an independent Bristol company, and these pages exist because the same questions come up on doorsteps every week — usually after someone has already been quoted for work that wasn’t theirs to pay for.
Some of this advice costs us work, deliberately. Telling you that hot water and a plunger will probably clear a slow kitchen sink, or that your neighbours having the same problem means it’s likely not your bill, loses us a job each time. It also means that when you do need someone, you know what you’re getting.
These guides are general information, not legal advice. Responsibility varies with tenure, tenancy terms and the specific property — check your position with Wessex Water, Bristol City Council or a solicitor.
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Areas we cover
Bristol, Bath and the towns around them, with what we find in each part of the city.
Still got a question?
Ring and ask. We don’t charge for answering questions, and if the answer is that you don’t need us, that’s what we’ll tell you.