How to unblock a toilet, and when the problem is further down

A blocked toilet is unpleasant but usually simple. Most blockages sit in the trap, the curved channel built into the pan just below the bowl, and a plunger used properly will shift them. The skill is knowing when it is not a pan blockage at all, and stopping before you make a mess or damage anything.

Stop flushing

If the bowl fills up and does not drain, do not flush again. Each flush adds another cistern-full of water to a pan that cannot empty, and the next one may overflow onto the floor.

If the water level is already near the rim:

1. Take the cistern lid off and lift the float or push the flush valve closed so it stops filling, or turn off the isolation valve on the pipe to the cistern if there is one.
2. Put old towels round the base of the pan.
3. Wait. A partial blockage often lets the level drop slowly over ten or twenty minutes, which gives you room to work.

Wear rubber gloves for everything that follows, and wash your hands and any tools well afterwards.

Is it the pan, or further down?

Before you start plunging, check what else in the house is doing.

• Only this toilet is slow, and the sink and shower in the same room drain normally: the blockage is most likely in the pan's trap or the short pipe behind it. Carry on with this guide.
• The toilet gurgles or bubbles when a nearby basin, bath or shower drains, or the bath fills with dirty water when the toilet is flushed: the blockage is probably in the shared waste pipe or the soil stack, the large vertical pipe that takes everything down to the drain. Plunging the pan rarely fixes that.
• More than one toilet is affected, a downstairs toilet backs up when one upstairs is used, or an outside gully or manhole is overflowing: the blockage is in the underground drain. See "When to stop" below.

The same check works the other way round. If a sink is slow, see our guide to unblocking a kitchen sink or basin.

Plunging a toilet

A toilet plunger works by pushing and pulling the water in the trap. It needs a seal and it needs water.

1. Make sure there is enough water in the bowl to cover the rubber cup. If the bowl is nearly empty, add some from a bucket. If it is nearly full, bail some out into a bucket first.
2. Put the cup into the bowl at an angle so it fills with water rather than air, then seat it over the outlet at the bottom of the pan.
3. Push down gently the first time, then pump firmly up and down a dozen or so times, keeping the seal. The pull stroke matters as much as the push.
4. Lift off and see whether the water drops away. Repeat a few times if it is moving.
5. When the level falls normally, test with a bucket of water poured in steadily before you trust a full flush.

A flanged toilet plunger, with an extra lip that fits into the outlet, usually seals better in a toilet than a flat sink plunger. Keep a plunger for the toilet only, for hygiene.

Do not use a wire coat hanger or a metal rod in the pan. It scratches the glaze and rarely reaches the blockage.

Things that commonly block a toilet

Wet wipes, even ones sold as "flushable", kitchen roll, cotton buds, sanitary products, nappies and too much toilet paper at once. Children's toys and small objects are common too. A solid object will not dissolve. If you know something solid has gone down, try to retrieve it with a gloved hand rather than pushing it further in.

Why not to pour in chemicals

Drain unblockers can be strongly caustic or acidic.

• Never mix two products, or follow one with another, and never use bleach alongside one. Mixing cleaners can give off dangerous fumes or react violently.
• Once a chemical is in the pan, do not plunge. It can splash back into your face.
• If you have used one and it has not worked, tell whoever comes to clear it what you put in.

A chemical will not move a solid object, and with a full pan the chemical is diluted before it reaches the blockage anyway.

Pan connectors and leaks

The pan connector is the plastic or rubber joint between the back of the pan and the soil pipe. If water appears behind or under the toilet only when you flush, the connector or its seal may be leaking, or the pan may have moved. That is not a blockage, and plunging can make it worse. A leak from the cistern or the pipe feeding it is a supply-side problem: see the guide to a running toilet and to finding a leak.

Replacing a pan connector means disconnecting the pan, which is usually a plumber's job unless you are confident lifting and refitting a toilet. See WC pan connectors.

When to stop and call someone

Stop and call a plumber or drainage company if:

• several goes with a plunger have not moved it;
• a solid object is stuck;
• more than one fitting is affected, or the bath, shower or basin backs up when the toilet is flushed;
• water is coming up from a gully or manhole outside, or there is a sewage smell in the house;
• water is leaking from the back of the pan or through a ceiling below;
• the toilet is a macerator type (a pumped unit, often behind or beside the pan). Do not plunge it or use chemicals unless the maker's instructions say you can. Follow the maker's instructions or call a specialist. See macerator toilets.

If the blockage looks like it is in a shared drain or past your boundary, contact your water company first. Shared drains and public sewers are often the water company's responsibility rather than yours. See outside drains.

Toilet plungers at Wickes

We haven't tested this. Figures are as the maker states them (checked 13 November 2026).

How long should I plunge a toilet before giving up?

Give it several rounds of firm plunging with rests in between. If the level does not move at all, or the toilet gurgles when other fittings drain, the blockage is probably further down and a plumber or drainage company is the next step.

Can I use boiling water to unblock a toilet?

It is best not to. Very hot water poured into a cold ceramic pan can crack it, and it will not shift a solid blockage. Warm water from the hot tap is gentler.

Is a blocked drain outside my house my responsibility?

It depends where it is and whether it is shared. Pipes serving only your property are usually yours, while shared drains and sewers are often the water company's. Contact your water company to check before paying for work outside your boundary.