Why a toilet drains slowly

A slow toilet means water is leaving the bowl more slowly than it should. The usual cause is a partial blockage in the pan, the bend or the drain beyond it. Because the blockage is only partial, the toilet still works, but badly.

Act early. A slow toilet can turn into a full blockage, and then it may flood the bathroom floor. Dirty water also carries a health risk, so keep children and pets away from it.

Try a plunger first

A plunger is the quickest thing to test, and it shifts many everyday blockages. Pull the rubber flange out first, since this gives a better seal. Keep enough water in the bowl to cover the plunger head.

Push in and out firmly, and keep the seal tight. After a few goes, the water should drop away. If it does not, try again, although do not keep going for long. Our guide to the best way to unblock a toilet without a plumber lists more safe options, and unblocking a toilet covers the basics.

Other simple steps

Warm water and a squirt of washing-up liquid can help to soften a soft blockage. Use warm water, not boiling, because boiling water can crack a toilet pan. Wait a while, then flush once to see what happens.

Stop if nothing changes. Further attempts can push the blockage deeper, and harsh chemicals can damage pipes. In particular, avoid mixing different cleaners.

When to ask for help

Call in a drainage engineer if the toilet stays slow after a plunger. The same goes if it has blocked before, because a repeat blockage suggests a fault further down. Gurgling in other fixtures is another warning sign.

The cause may not be in the toilet at all. A fault in the drain run can slow every fixture, so read blocked drain pipe: branch blockage or main-run failure to see the difference. If sewage is rising, send an enquiry straight away, as our emergency drain unblocking page explains.

What an engineer does

An engineer may take apart the bend, clear the blockage, degrease the pipe and refit it. For a drain fault, jetting is often the answer, as we describe in how drain jetting can benefit you. A camera can then confirm the pipe is clear. If a pipe has failed, see collapsed drain repair for the next steps.

A camera survey helps when the cause is unclear. We explain what changes the price of a CCTV survey in a separate guide.

What it costs

There is no standard price, because jobs differ. A soft blockage in an easy ground-floor toilet is quite different from a collapsed pipe under a solid floor. Our guide on how much it costs to unblock a drain lists the factors.

We agree a fixed price before work starts, with no call-out fee. Tell us what the toilet does and where you are, and we will give you a figure. Use the online enquiry form to start.

Stop it happening again

Flush only toilet paper. Wipes, cotton wool and nappies block pipes even when the packet says flushable. Regular cleaning also helps, and how often drains should be cleaned gives a sensible routine. Sewage drains need their own care, which we cover in how to unblock a sewage drain.

Help in North London

We offer blocked toilet clearance and wider blocked drains help. Our area includes blocked drains in Barnet, drain unblocking in Edgware and blocked drains in Wembley.