Does fairy liquid unblock drains?

A sink that drains in slow spirals, or a gully that brims after rain, already tells you where the blockage probably sits. Our Drain Cleaning work across Surrey, London and the South East starts from that clue, and so can you before reaching for the bottle under the sink.

Heating Services Ltd is Gas Safe registered and has worked in the area since 2008, with a team of locally based drainage engineers. We cover drain cleaning across the region, from cleaning drains in Cheshunt to every town around it.

Tell Heating Services Ltd what your drain is doing and a drainage engineer can usually reach you anywhere in Surrey, London and the South East the same day.

Does fairy liquid unblock drains?

Fairy liquid can unblock drains when the blockage is soft fat, oil and grease in a kitchen sink or waste pipe, because washing-up liquid is a degreaser and emulsifier that loosens it so hot water carries it away. It will not clear hair, wipes, food solids, or the leaves and twigs, silt and mud that block outdoor drains.

What you can clear yourself and what needs a drainage engineer

Fairy is a brand name. What matters is what is in the bottle. Any washing-up liquid breaks fat, oil and grease into small droplets that stay suspended in water, which is why it lifts a greasy pan. A concentrated liquid does more per squirt, but an own-label one works on the same principle.

That makes it a reasonable first try on a slow kitchen sink, where cooking grease coats the trap and the first stretch of waste pipe. It is far less useful elsewhere:

• Bathroom basins and showers: the usual culprit is hair bound together with soap residue. Washing-up liquid can loosen the soap, but matted hair has to be pulled out of the plughole or the trap, or hooked out with a plumber's snake.
• Toilets: a squirt of liquid and a bucket of hot tap water can ease a soft paper blockage. It does nothing for wipes, sanitary items or a child's toy.
• Outdoor drains: gullies and inspection chambers fill with leaves and twigs, silt and mud, none of which is greasy. Lift the grate wearing gloves, scoop out the trapped debris and flush with a bucket of water. Drain rods can shift what is left, provided you know which way the pipe runs.

Bring in a drainage engineer when several fittings are slow at once, when one plughole gurgles as another drains, when an outdoor gully or manhole fills and stays full, or when the same sink blocks again within weeks. Those signs point to the shared drain. Our engineers find the cause with CCTV drain cameras and sonar pipe location rather than digging, then clean the drain or repair a cracked or slipped section.

Safety points before you pour anything

Washing-up liquid is mild. The hot water that goes with it is not, and neither is anything already sitting in the pipe.

• Keep the water off the boil. Most modern waste pipes are plastic, and water straight from a boiling kettle can soften joints and distort the pipe over time. Let the kettle stand for about five minutes first. Never pour boiling water into a toilet: the sudden heat can crack a ceramic pan.
• Never combine it with chemical drain unblockers. If you have already poured in a caustic or acid product, add nothing else and do not plunge, because the mixture can splash onto skin and into eyes. Tell whoever attends exactly what went in.
• Protect yourself. Wear rubber gloves and keep your face away from the plughole while pouring. Standing water in a blocked sink is dirty water.
• Do not force rods blind. Pushing hard into a pipe you cannot see can dislodge a joint and turn a blockage into a repair.

The washing-up liquid method, step by step

This suits a greasy kitchen sink and is worth a try on a sluggish basin. Give it two or three rounds before you decide it has failed.

• Empty the bowl. Bail standing water into a bucket with a mug, so the liquid reaches the blockage instead of diluting on top of it.
• Add the liquid. Squeeze three or four tablespoons of washing-up liquid straight down the plughole.
• Wait. Leave it for 20 to 30 minutes. It is denser than water, so it sinks towards the trap and works into the grease.
• Follow with hot water. Pour about two litres of hot water, off the boil, slowly and in stages. A slow pour keeps the heat in the pipe for longer.
• Test, then repeat or plunge. Run the hot tap for a minute. If it is better but still slow, repeat once, then use a sink plunger with the overflow covered by a damp cloth so the pressure goes down the pipe.

If nothing changes after a few rounds, the blockage is either not grease or sits beyond anything poured from above. Stop there.

Common mistakes that make a blockage worse

The biggest misconception is that a squirt of washing-up liquid makes it safe to pour cooking fat down the sink. It emulsifies the fat for a few seconds, but as the water cools further along the pipe the droplets join up again and set on the pipe walls, usually where you cannot reach them. Scrape fat and oil into the bin and wipe greasy pans with kitchen roll before washing.

Other common mistakes:

• Treating every outdoor blockage as weather. Leaves and silt are common after storms, but a gully that keeps refilling in dry spells may have roots or a displaced joint behind it, which a CCTV survey will show.
• Clearing the same sink every week. That routine is a symptom: the waste pipe or the drain beyond it is narrowing, and proper drain cleaning removes the build-up instead of punching a small hole through it.
• Using more and more liquid. A bowl of foam does not clear grease faster, and the suds can back up into a second sink.

If your blocked drain has gone past what a kettle can help with, our drainage engineers work across Surrey, London and the South East and live locally, so someone can usually be with you the same day. They will explain what they found and what it needs before any work starts.