Common causes of smelly drains

Cracked pipes

Hairline cracks occur in earthenware or clay pipes causing the water in the trap to continually drain away.

Siphonage

Hair strands hanging over the weir cause siphonage.

Evaporation

Common in plant rooms, cool rooms, laundries, hotel rooms, holiday homes, etc. due to periods of infrequent use.

Toilet waste in the floor waste

A commonly occuring situation is a blockage due to tree or grass roots, or high volume use downstream of where a toilet has been flushed. The waste from the toilet momentarily travels upstream at which point it can flow into the floor waste becoming trapped there.

When the basin is used and the water flows through to the floor waste, it stirs up the contents and the offensive odours emanate into the habitable area.

Venting

Poor venting of the plumbing system will also cause the water seal to be reduced, allowing the flow of sewer gases into the habitable area.

Defective plumbing

In some cases a trap or water seal has not been installed in the drainage system.

CRACKED PIPES

SIPHONAGE

EVAPORATION