How to Unblock a Toilet, and How to Tell When It's the Drain

To unblock a toilet, stop flushing, bail the pan down to about half full, and work a cup plunger with a flange firmly over the outlet for twenty or thirty strokes. If that does not shift it, a toilet auger usually will. But before you spend an hour on it, check one thing: whether anything else in the house is draining badly. If the bath, shower or a downstairs gully is also slow or rising, the blockage is in the drain below the toilet, and no amount of plunging will clear it.

First, check whether it is the toilet or the drain

If only the toilet is affected and every other sink, bath and shower drains normally, the blockage is in the toilet or the short pipe behind it. If other fittings are slow, gurgling or backing up, or the manhole outside is full, the drain is blocked.

Two quick checks settle it. Run a basin or shower on the same floor for a minute and watch the toilet pan: if the water level in the pan rises or bubbles, they share a blocked pipe further down. Then lift the cover of the manhole or inspection chamber nearest the house, usually in the front or back garden, a side passage or under a paving slab. If the chamber is empty and the channel at the bottom is clear, the drain is fine and the problem is upstream in the toilet. If it is full of standing water or sewage, the blockage is below it, and our note on whether you need a plumber or a drainage engineer explains the split in more detail.

A pan that fills almost to the rim and then slowly drains away over ten minutes or so is the classic sign of a partial blockage in the toilet itself. A pan that stays full, or a ground-floor toilet that rises when someone upstairs flushes, points to the drain.

How to unblock a toilet with a plunger

Use a flanged cup plunger, not the flat sink kind, and make sure there is enough water in the pan to cover the cup. The flange seals into the outlet so that each push drives water against the blockage rather than splashing it back round the bowl.

• Protect the floor. Put old towels round the base and wear rubber gloves. Keep children and pets out of the room.
• Get the water level right. If the pan is nearly full, bail some into a bucket so it will not slop over. If it is nearly empty, add water from a jug until the cup is covered.
• Seat the plunger and push gently first. The first push forces the air out of the cup. After that, push and pull firmly and steadily for twenty to thirty strokes, keeping the seal.
• Lift it off and watch. If the water drops away with a gurgle, the blockage has moved. Pour in a bucket of cold water to check before you risk a flush.
• Flush once, with your hand on the cistern. If the level starts to rise again, lift the float or close the flush valve to stop more water coming in.

If three or four rounds of plunging make no difference, stop. Carrying on rarely helps and splashes contaminated water around the bathroom.

When a plunger is not enough: the toilet auger

A toilet auger, sometimes sold as a closet auger, is a short hand-cranked cable in a protected sleeve that reaches round the bend in the pan. It will pull out or break up most things a plunger cannot, such as a wad of wipes or a child's toy.

Feed the end into the outlet, crank the handle as you push, and draw it back slowly. The rubber sleeve stops the cable scratching the glaze. Ordinary drain rods or a wire coat hanger are a poor substitute: they scratch the pan, and pushing hard at an object that is jammed can wedge it further into the trap.

An auger only reaches about a metre. If it goes through freely and the pan still will not drain, the blockage is past the toilet, in the soil pipe or the underground drain.

What not to put down a blocked toilet

Do not use boiling water, and do not pour chemical drain unblockers into a pan full of standing water. Boiling water can crack a vitreous china pan, and a chemical unblocker diluted in a full bowl does little except make the water dangerous to whoever clears it next.

Washing-up liquid followed by a bucket of hot tap water, poured from waist height, will sometimes loosen a soft blockage of paper. It is worth one try. What it will not do is shift wipes, sanitary products, nappies or cotton wool, which are behind most of the blocked toilets we see.

If the toilet is already overflowing when you flush, deal with that first: stop the cistern refilling and turn off the isolation valve, as set out in our page on a toilet overflowing when you flush.

When a blocked toilet needs someone tonight

It needs attention tonight if it is the only toilet in the property, if sewage is coming up in a shower or floor drain, or if a ground-floor toilet is backing up whenever anyone else uses water. It can usually wait until the morning if there is a second working toilet and nothing is overflowing.

A single blocked toilet in a house with another bathroom is an inconvenience, not an emergency, and you will pay less by booking it for the day. The picture changes in a flat with one toilet, a household with young children or someone unwell, or a building where several flats share the same stack. When the drain rather than the toilet is blocked, everyone upstream keeps adding to it every time they flush.

Our blocked toilet and internal drain clearance covers the toilet, the soil pipe and the underground drain behind it, using an auger or rods inside and a jetting unit through the manhole where the blockage is outside. Our rates are set by the clock: 7am to 5pm is the standard rate, 5pm to midnight the evening rate, and midnight to 7am the night rate. The current figures are on our pricing page and the price is agreed on the phone before anyone travels.

Why toilets keep blocking, and what stops it

A toilet that blocks once is usually down to something that should not have been flushed. A toilet that blocks every few weeks usually has a problem further down the pipe that catches paper as it passes.

Wipes, including those labelled flushable, are the most common cause of a single blockage. Repeated blockages often come from a partial obstruction in the drain, such as a displaced joint, a root intrusion, a build-up of scale in an old cast-iron stack or a sag in the pipe where waste settles. Low-flush cisterns in older pipework can also struggle to carry paper far enough in one go.

If you are plunging the same toilet every month, it is worth having the drain looked at with a camera once it has been cleared, so that the cause is found rather than cleared again next time. Until then, a bin in the bathroom and a clear word with anyone who uses it will prevent most repeat call-outs.