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Some blockages give way to ten minutes and a plunger. Others are the ground itself telling you something. Four stops to tell which you've got.
What do I do about a blocked drain right now? Stop running water into it, try a plunger with the overflow blocked off, and check your outside gully for anything obvious. If the water won't shift, or more than one fixture is backing up, ring 020 4577 2888 to be put through to a local plumber — pushing on with chemicals rarely ends well.
Count what's misbehaving. One slow sink is a local clog you might clear yourself; several fixtures backing up or gurgling together means the blockage is further down the line.
This one question decides your whole evening, so answer it before touching a plunger. Run through the house: is it just the kitchen sink, or is the bath slow too? Does the toilet gurgle when the basin empties? Is there water standing in the outside gully?
A single misbehaving fixture usually means hair, grease or food waste sitting in the trap or the first stretch of waste pipe — annoying, local, and often fixable by hand. But when fixtures start talking to each other — a gurgle here when water drains there, or the lowest drain in the house backing up first — the blockage sits in a shared pipe below all of them, and no amount of plunging one plughole will reach it. That's the point to think about the drain run as a whole, and usually the point to bring in someone with rods or a jetter.
Trap, plunger, gully — in that order, and with patience. These three clear the honest majority of single-fixture blockages.
What to skip: pouring kettle after kettle of boiling water into plastic pipework, cocktail-mixing chemical uncloggers, and poking improvised wire down the WC — a bent coat hanger scratches pans and pushes blockages tighter more often than it retrieves them. If your three honest attempts haven't moved it, the blockage has won round one; give a plumber round two.
Fat, wipes, and anything that isn't the three Ps — pee, poo, paper. Nearly every kitchen blockage and most bathroom ones start with these.
Cooking fat is the great deceiver: it pours away as an innocent liquid and sets in the pipe as something close to candle wax, catching every crumb that follows. Let it cool, jar it, bin it. "Flushable" wipes are the other repeat offender — flushable in the sense that they disappear from the bowl, not in the sense that they break down. They don't, and they knit together with fat into the lumps that drainage engineers pull out of pipes every week.
Add to the never list: coffee grounds, rice and pasta (both swell), plaster and grout from DIY jobs, cotton pads, and cat litter. One habit protects a house more than any gadget: a sink strainer in the kitchen, and a bin beside the toilet for everything that isn't paper. Plenty of properties out through the Lecale countryside run on a septic tank rather than mains drainage, and there all of this counts double — a tank forgives even less than a sewer does, and fat or wipes can shorten the time between emptyings considerably.
Rough rule: your pipes, your problem — the shared and public bits are generally NI Water's. If the neighbours are backing up too, it's probably not your blockage.
The boundary works broadly like this in Northern Ireland: drains inside your property boundary that serve only your home are the owner's responsibility, while public sewers — and shared sewers beyond the boundary — generally fall to NI Water. So a blocked kitchen waste or a single overflowing gully is your side of the line; a public manhole lifting in the street, wastewater surfacing on the road, or several houses on the same terrace backing up at once points to the public network, and that gets reported to NI Water rather than paid for out of your pocket.
Worth knowing locally: parts of the town sit low near the Quoile and its marshes, and standing water after heavy rain in those spots is often surface flooding rather than a sewer problem at all — different call entirely. The older streets under the cathedral, where terraces share drainage runs laid generations ago, are exactly where the "is it mine or ours?" question comes up most often. A quick word with the neighbours before you book anyone can save you a call-out fee — and a plumber worth their salt will tell you plainly when the blockage isn't on your side to fix.
Use them sparingly, if at all. They can shift light grease near the plughole, but on a solid blockage the caustic liquid just sits in the pipe — and the next person to plunge or rod that drain gets a splash of it. If one dose hasn't worked, stop pouring and switch to mechanical methods or a professional.
Gurgling is air being dragged through water where it shouldn't be, and when one fixture talks while another drains, they're arguing over a partly blocked shared pipe. It's an early warning worth heeding — drains rarely unblock themselves, and the gurgle usually comes before the overflow.
Broadly: the drains inside your boundary serving only your property are yours; public sewers, and shared sewers beyond your boundary, are generally NI Water's territory. If several houses back up at once, or a public manhole is overflowing, report it to NI Water. If it's just your own gully or WC, it's your side — and a plumber is the right call.
The pipework running to it, yes — the tank itself and its emptying schedule is more often a specialist job. A plumber can tell whether a slow-draining system is a blocked run of pipe you can fix, or a tank that's simply due to be emptied, and point you the right way either way.
It's the drain telling you the blockage is beyond that point, not in the sink you've been plunging. Lift the gully grid if you can and clear any leaves or silt — that alone fixes a surprising number. If the gully itself stays full or wastewater keeps rising, the run below ground needs rodding or jetting, which is professional work.
The main page — how the line works and the areas it covers.
Go to home →The first five minutes, in the right order.
Read the guide →Pressure drops, no heat, error codes — and gas safety.
Read the guide →Honest ballparks and the questions to ask before work starts.
Read the guide →Pressure, controls, the immersion — the checks before you call.
Read the guide →Thawing safely with gentle heat — and the lagging that prevents it.
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