You walk into the bathroom and there's that smell: like rotten eggs or a blocked sewer. The drain isn't blocked, the water goes down fine, but the smell keeps coming back. Here's what usually causes it, and how to get rid of it.
Why drains smell
Every sink, shower and bath has a trap, the U-shaped bend under the plughole. It holds a little water that blocks sewer gases from coming up into your home. Most drain smells happen because that water seal is missing, or because something is rotting inside the trap.
Check these first
- A drain you don't use. In a spare bathroom or a shower nobody uses, the water in the trap dries out. Run the tap for a minute and the smell often goes.
- Hair and soap in the trap. This is the usual cause of a smelly shower drain that isn't clogged. Lift the cover, pull out what you can, and clean the trap.
- Food and grease in a kitchen sink. Unscrew the trap under the sink (put a bowl underneath first), clean it out, and screw it back on firmly.
- The washing machine or dishwasher hose. Dirty water left in the hose or its connection can smell. Run a hot empty wash.
A simple clean that often works
Pour a kettle of hot (not boiling) water down the drain, then half a cup of bicarbonate of soda and a cup of white vinegar. Leave it for 30 minutes and flush with hot water again. Avoid using lots of strong chemical drain cleaners. They can damage seals and older pipes.
When the smell is from outside or everywhere
If the smell is strongest outside, near a drain cover, or comes from several rooms at once, the problem may be in the main drain: a partial blockage, a cracked pipe, or a broken vent. Signs include slow drains in more than one place, gurgling noises, or water backing up outside. Read about blocked drains, or call us and we'll find the source.
Common questions
Why does my shower drain smell but isn't clogged?
Hair and soap in the trap start to rot, or the water in the trap has dried out. Clean the trap and run water through it.
Why does my house smell of drains?
Usually a dry trap in a room you don't use. If the smell is everywhere, or strongest outside, the main drain may be partly blocked or damaged.
How do I get rid of a drain smell quickly?
Run hot water, then add bicarbonate of soda and white vinegar. Leave it 30 minutes and flush with hot water.