Drain Smells

Start with traps and connections

A trap that has dried out leaves an open air path to the drainage system. Poor seals around wastes or toilets can do something similar even when the drain itself is sound.

Smells outdoors

Deposits in a gully, a loose chamber cover or a drainage defect can all produce odour outside. If the smell appears only when appliances discharge, look at how the system is venting and whether wastewater is backing up.

When a camera survey is worth considering

Camera inspection becomes more relevant where there are repeated blockages, visible damage, unexplained leakage or evidence that the smell is associated with a specific underground run.

When the smell appears can give you a clue

If the smell comes from a shower that has not been used for weeks, pour water into the trap before investigating underground drains. If the smell appears whenever a toilet is flushed, or is strongest at an outside chamber, look instead at seals, covers and the drainage route serving that area.

Before anyone starts digging because of a smell, check the simple things first. A dry trap, loose seal or poor waste connection can let drain smells into a room without there being anything wrong with the underground drain.