Sink overflow stinks - what causes it?


If bad smells penetrate from the washbasin, this can also be due to the overflow. Why this is so, and what measures and remedies there are, read in detail in this post.

Construction of the overflow

The overflow is a cavity in the interior of the washbasin. The overflow then empties into the drain valve and the overflowed water from there into the drain pipe.

The purpose of the overflow is to protect the sink from overflowing when its drain is closed.

Problem with the overflow

The problem lies in this case in the fact that even when not in use of the overflow dirt and also some water get in there. If the water drains from the washbasin, water can also enter the overflow due to a short backwater.

It collects there together with the infiltrated dirt and forms a very ideal breeding ground for decomposing microorganisms. This can cause fällnisgerüche, which then escape from the overflow opening.

Remedy: Clean the overflow

In the cavity inside the washbasin you have no access from the outside. So you can not clean the entire area behind the overflow opening.

However, it is possible to rid the area indirectly of dirt. How exactly this works, read in this post.

By cleaning dirt particles are released and the cavity is thoroughly rinsed. This removes most of the odor causing mud from the cavity. You can use different cleaning agents:

  • cleansing foam
  • Drain cleaner (less recommended)
  • mold cleaner
  • disinfectant

Tips & Tricks

Always remember the siphon for bad smells from the sink. He can also be easily removed and cleaned, if necessary, also thoroughly inside with a brush. How this works, we have described in detail in this article.


Video Board: Sink odors from overflow holes cleaned with enzyme cleaner by ZEP