Seven signs of
a blocked drain.

1. Water drains more slowly than usual

A sink, bath or shower that takes longer to empty may have a local build-up close to the fixture. If several fixtures are slow, the obstruction may be further along shared pipework.

2. Gurgling or bubbling sounds

Unusual noises after water drains can mean air is being displaced by a restricted pipe. Notice whether the sound comes from the fixture in use or from another nearby outlet.

3. Unpleasant drain smells

Persistent odours may be linked to trapped debris, an empty water trap or a drainage fault. A smell alone does not identify the cause, but it is useful to note where and when it appears.

4. Water rises in another fixture

If flushing a toilet makes water appear in a shower tray, or emptying a sink affects another outlet, connected pipework may be restricted. Stop using the affected fixtures until the problem is assessed.

5. The toilet water level changes

A toilet that fills unusually high, drains slowly or has a noticeably different standing-water level can indicate a partial blockage. Avoid repeated flushing if the level is already rising.

6. An outside drain is overflowing

Standing wastewater, debris or an overflowing gully outside needs prompt attention—particularly if it worsens when taps, toilets or appliances are used indoors.

7. The problem keeps returning

A fixture that blocks repeatedly may have a deeper restriction, damaged pipework or another underlying cause. Clearing the immediate symptom may not resolve the reason it keeps happening.

What not to do

Do not mix chemical drain cleaners or add a second product after the first has failed. Chemicals can react, create hazardous fumes or make later work more dangerous. Avoid dismantling pipework if wastewater is backed up or you are unsure how the system is arranged.

Details worth noting

Record which fixtures are affected, whether the problem is inside or outside, when it began, whether it changes when another fixture is used and whether it has happened before.