Skip to content
Manage My Life

Why is there a sewer gas smell from my sink?

I recently remodelled my bathroom and put in a new sink and plumbing but I am having the same problem as before. Whenever we turn on the faucet there is smell of sewer gas. The plumber told me to fill the sink with water till it flows through the overflow hole and add bleach. This took care of the smell for about a month, and now it is back. What can be done?

Building Supplies
Sign in to answer a question
1 Answer from this member:
Manage My Life
There are two possible causes of the smell of sewer gas: 1) The waste plumbing is not properly trapped and vented. The trap below the sink prevents sewer gases from entering, because it is full of water. The waste plumbing is also vented to allow water to flow freely and to prevent the water from being siphoned from the trap.

If your bathroom was professionally remodelled, there shouldn't be a problem with the waste plumbing configuration. 2) The more likely scenario is as your plumber suggests. For some reason, a more than average amount of foreign material is getting into the overflow tube that runs from the overflow hole in your sink, to the drain at the base of your sink. Water flowing down the drain forces air back up though the overflow. Decaying material in the overflow pipe then gives off a smell. (This is why kitchen sinks don't have an overflow. Food particles caught in the overflow would smell.) This is why the bleach down the overflow worked. You can verify this by temporarily taping over the overflow and running water. The solution is to use bleach regularly or prevent foreign material from entering the overflow.
by Manage My Life
April 26th, 2007
Answered in 0 seconds
0 votes
Didn't find what you are looking for? Ask a question
Get up to
% off
On Building Supplies