How to use a plunger properly on a toilet, sink or bath

Which plunger for which fitting

Most failed plunging comes down to using the wrong plunger. A plunger only works when it can seal against the surface around the outlet and trap water in the pipe. A flat cup cannot seal inside the curved outlet of a toilet pan, and a toilet plunger's sleeve gets in the way on a flat sink.

Before you start

Take two minutes to get the conditions right. It makes the difference between a blockage that clears in a minute and one that just sloshes around.

• Stop running water or flushing, so the fitting cannot overflow while you work.
• Put old towels down and wear rubber gloves. Plunging can splash, and a toilet blockage is not clean water.
• Do not plunge if you have already poured in a chemical drain cleaner. Splashback can burn skin and eyes. Flush with plenty of water first if you can, or leave it for a plumber and tell them what was used.
• Remove any removable plug, pop-up waste cap or hair trap so the plunger works on the pipe, not a loose part.
• Check whether other sinks, the bath, the shower or an outside drain are also slow. If they are, the problem is in the shared drain and plunging one fitting will not fix it.

How to plunge, step by step

The technique is the same on every fitting. What changes is how you seal it.

• Make sure the rubber cup is covered by water. If the fitting has drained low, add a little from a jug. Air compresses, water does not, so plunging air achieves very little.
• Put the plunger in at an angle so the cup fills with water rather than trapping a bubble of air.
• Seat it squarely over the outlet so the rim is flat all the way round.
• Push down gently first to push out any air, then work it firmly up and down 10 to 15 times, keeping the seal. Think of it as pulling as much as pushing.
• On the last stroke, pull the plunger off sharply. Watch whether the water starts to drop.
• Repeat for three or four rounds if the water is moving a little each time. If nothing changes at all after that, stop.

Sealing the overflow on a sink or bath

Basins and baths have an overflow, a slot or hole near the top that joins the waste pipe below. When you plunge, the pressure escapes through the overflow instead of reaching the blockage. Hold a wet cloth tightly over the overflow, or ask someone to, while you plunge. You will feel the difference straight away.

Double kitchen sinks work the same way. Both bowls share one trap, so block the second plug hole with its plug or a wet cloth held down firmly, or the water will just rise and fall in the other bowl. A dishwasher or washing machine connected to the sink waste can also let pressure escape through its hose; the hose normally has a loop or non-return valve, but if water comes back into the machine, stop.

For the fitting-by-fitting detail, our guides on how to unblock a sink and how to unblock a bath cover traps, plugs and overflows, and when it is easier to take the trap off instead.

Plunging a toilet

Use a flange plunger with the sleeve folded out, and put the sleeve right into the outlet at the bottom of the pan. Make sure there is enough water in the bowl to cover the cup, but not so much that it will overflow when you push. If the bowl is full to the rim, wait for it to drop a little or bail some out into a bucket.

Work it the same way: 10 to 15 firm strokes, keeping the seal, then a sharp pull. When the water level drops suddenly with a gurgle, the blockage has usually moved. Test with a bucket of water poured in steadily rather than a flush, so that if it has not cleared you have not filled the bowl again. Our full guide on how to unblock a toilet also covers warm water and a toilet auger.

Where a plunger will not help

A plunger clears blockages close to the fitting: soap and hair in a basin trap, fat and food in a kitchen trap, too much paper in the toilet bend. It cannot clear a blockage in the underground drain, and it cannot move a solid object such as a toy, a phone or a toilet block holder that has wedged in the trap. Plunging something solid can push it further in and make it harder to get out.

Signs that the blockage is beyond the fitting include water coming up in the shower when the toilet flushes, a gurgling sink when a different fitting is used, an outside gully or inspection chamber that is full, and a smell of sewage. At that point, the job needs drain rods or a jetter from the outside, and our guide on why drains keep blocking explains the usual causes.

Plungers are also not for macerator toilets such as a Saniflo, or for a sink with a waste disposal unit. Both have their own reset and clearing methods in the manual.

If sewage is coming up through a toilet, shower or floor drain, stop using water in the whole house and get the drain cleared from the outside. Plunging will only push more water towards the blockage.

When to call a plumber

Stop and get help if three or four rounds of proper plunging make no difference, if more than one fitting is affected, if water is overflowing onto the floor, or if something solid has gone down. Keep the fitting out of use until it has been looked at.

Loyal Plumbers clears blocked toilets, sinks, baths and drains across London and everywhere inside the M25, 24 hours a day, with 10 vans on the road. Our call-out charge is £60. Call 020 4652 8585 or send an enquiry saying which fittings are slow or backing up and what you have already tried.