What are common signs of a blocked drain?

Slow drainage, gurgling noises, foul odours, water backing up, and wet patches above drains are typical warning signs.

Why does my sink gurgle?

Gurgling often means trapped air in the pipes caused by a partial blockage or venting issue.

What does sewage smell indoors mean?

Sewage smells can indicate trapped waste, dry traps, or blockages deeper in the drainage system.

If wastewater is backing up into sinks, toilets, or onto the ground, treat it as urgent and seek help immediately.

Signs of a Blocked Drain

How to spot the warning signs early and what they usually mean for your drainage system.

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1. Slow drainage

Water pooling in sinks, baths, or showers often means a partial blockage restricting flow. If multiple fixtures are slow, the problem is likely deeper in the system.

2. Gurgling noises

Trapped air escaping as water struggles to pass obstructions creates gurgling sounds. Common in sinks, baths, and toilets when blockages are developing.

3. Foul odours

Smells indoors or around outside gullies often indicate trapped waste, stagnant water, or poor ventilation caused by a blockage.

4. Water backing up

Wastewater rising in toilets, sinks, or external gullies is a strong sign of a severe obstruction. This is usually urgent and can escalate quickly to flooding.

5. Wet ground or patches

Unexplained damp or boggy areas in gardens can point to a blockage, leak, or soakaway/drainage field issue. If persistent, it may indicate a structural defect.

What to do if you notice these signs

Try basic checks (rodding a gully, plunging a sink) if safe.
Avoid chemicals if unsure — they can harm pipes and the environment.
If multiple fixtures are affected, request a CCTV survey.
For recurring issues, consider jetting or lining depending on survey results.

Related: Drainage