Home › Blocked drains
Half of drain wisdom is handed down like a family recipe, and about as scientific. Here's what actually clears a blockage, what quietly builds one, and when the problem isn't yours to fix at all.
Drain blocked right now? Stop running water into it, try a plunger with a decent seal, and don't reach for caustic chemicals as a first move. If more than one fixture is backing up, or sewage is appearing at an outside gully, that's a main-drain job — call 020 4577 2888 to be connected with a local plumber, any hour.
For a single slow or blocked fixture, the unglamorous tools earn their keep: a plunger with a proper seal over the plughole (block the overflow with a damp cloth so you're compressing the blockage, not the air), a drain snake or a straightened wire for hair within reach of the trap, and unscrewing the U-bend under a sink with a basin underneath — the blockage is very often sitting right there, looking guilty.
MythA kettle of boiling water clears any blockage.
FactHot water with a squirt of washing-up liquid can shift light, greasy build-up in a kitchen waste. Boiling water, though, is a blunt instrument: it does nothing against wipes, hair mats or scale, and it can soften plastic pipework and stress seals — especially in older systems. Warm and patient beats boiling and hopeful.
MythChemical unblocker is the strongest option, so start there.
FactChemicals are the option with the most side effects, not the most strength. Caustic cleaners sit in the pipe when they fail, turning the standing water in your sink into something you really don't want to plunge splashes out of. They're hard on old pipework and on whoever eventually clears the drain by hand. Mechanical first; chemicals rarely, carefully, and mentioned honestly to anyone who comes to help afterwards.
MythHot fat is a liquid, so it flows away like everything else.
FactIt flows exactly as far as the first cold stretch of pipe, where it sets, layer by layer, into a deposit with the ambition of a stalactite. Fat, oil and grease go in a container and then the bin. The same courtroom logic applies to "flushable" wipes: they leave the bowl, they don't break down, and they meet the fat downstream to form blockages with real staying power. Toilet paper and what nature intended — nothing else goes down the loo.
This is the diagnosis that decides whether tonight involves a plunger or a professional. One slow sink is a local problem. But when the downstairs loo backs up as the bath drains, several plugholes gurgle in chorus, or water and worse appear at the outside gully, the blockage is downstream where everything meets — the main drain. In Portadown's older red-brick terraces, shared and Victorian-era drain runs make a main-drain blockage more of a neighbourhood event than a private one; and in low-lying spots near the Bann, prolonged wet weather makes outside gullies work harder, so a partial blockage that limped along all summer can announce itself in the first proper downpour.
MythIf the toilet still flushes, the main drain must be fine.
FactA partially blocked main drain will keep accepting flushes right up until it doesn't — usually the evening you have guests. Gurgling, slow draining across several fixtures, and smells from plugholes or the gully are the early warnings. Acting on the warnings costs a fraction of acting on the flood.
MythEverything past the back door is the water company's problem.
FactBroadly, drains serving only your property inside your boundary are yours; public sewers, including most shared sewers beyond the boundary, are NI Water's business in Northern Ireland. The useful clue is company: if neighbours are backing up at the same time as you, the problem is likely on the shared or public side — worth establishing before anyone pays to clear a drain that was never theirs. Older layouts can be quirky, so if in doubt, ask the plumber to help identify whose drain is actually blocked.
Sometimes, on light organic build-up — but they're caustic, hard on older pipework and seals, dangerous if they end up mixed in a standing pool you then plunge, and useless against solid obstructions like wipes or scale. Try mechanical first: a plunger, or a drain snake for reachable blockages. If you have used chemicals, say so when someone comes to clear it, for their safety.
They flush, in the sense that they leave the bowl. They don't break down the way toilet paper does, and they're a leading cause of blocked drains and sewers across the UK. Wipes, cotton wool, sanitary products and kitchen roll all belong in the bin — the label's optimism is not an engineering standard.
Broadly: drains serving only your property, within your boundary, are the owner's responsibility, while public sewers — including most shared sewers beyond your boundary — are a matter for NI Water in Northern Ireland. If neighbours are backing up at the same time as you, that points to the shared or public side. Responsibilities can vary with older or unusual layouts, so check before paying for work on a drain that may not be yours.
Gurgling is air being dragged through water traps because it can't move freely through the pipework — an early sign of a partial blockage or a venting problem somewhere downstream. One gurgling fixture is worth watching; several fixtures gurgling together suggests the main drain, and it's much cheaper to deal with while water still drains at all.
The main page — how the line works, areas covered, and the big myths.
Go to home →Stopcock first, towels later — and whose pipe it is when the leak is outside.
Read the guide →Pressure, lockouts, noises — and the gas rule that has no exceptions.
Read the guide →Hedged national ballparks and the questions to ask before work starts.
Read the guide →Pressure, timers, tripped switches and the diverter-valve giveaway.
Read the guide →Gentle heat from the tap end, never a flame — and the lagging that prevents it all.
Read the guide →Damp patches, dropping pressure and the honest stopcock test.
Read the guide →Any hour, any day — be connected with a local plumber covering Portadown, Craigavon, Lurgan and the surrounding County Armagh area.
Call now