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Foul Smell Under The Sink? (What’s The Cause?)

The kitchen's workhorse, without question, is the sink. Weekly, how much food waste and grease do you dump down there? Sink drain odors may be a nuisance for homeowners from time to time. This is when we can come in handy as there is so much to learn about drains!

Reasons for a Foul Sink Drain Smell

Ventilation problems

Vent pipes can also trap sewer gas. Your home's roof is the final destination for the sewer gasses that travel through these pipes. Snow, birds' nests, or leaves can clog the pipes and force the sewer gas into your home's drains. If you didn't know, your drains and roof have many in common.

Rotting food

The scent in your kitchen sink was probably caused by rotting food. On this list, it's perhaps the most prevalent culprit. Food particles may become stuck in your drain or trash disposal if you dump food down the drain a lot. However, even if everything goes smoothly, even a little food left in the drain spoils and emits an unpleasant stench.

Dry p-trap

The p-trap is a little-known plumbing feature that many homeowners don't know about. All of your home's sinks have a p-trap fitted below them. Its primary function is to prevent debris from being flushed down the drain. By doing this, the plumbing system is kept free of obstructions, even at the deepest levels. It also serves to keep sewage gas out of the house. Those debris-trapped scents are discharged when the p-trap becomes too dry.


Surface-level obstructions are also a prevalent cause of a smelly sink drain. Clogs in your drains are caused by hair, food, grease, soap, and other items becoming caught in them. As time passes, these blockages decompose and gather more dirt and debris. There is a gradual accumulation of odors until you are compelled to act on them.