Return to the Plumbing Forum | Post a Follow-Up

Sewer gas smell in the basement bathroom

Posted by kaismom (My Page) on
Wed, Mar 7, 07 at 12:04

Our house is three story with plumbing on every floor. In the basement bathroom only, there is intermittant sewer smell. Everything flows extremely well without being sluggish.

In the offending bathroom, we replaced the wax seal of the toilet. We poured boiling water down the shower drain. The smell is faint but persistant and intermittantly worse.

My husband cleaned out the shower trap and noted that the sewer gas was coming out at him with "increased pressure". Having worked on plumbing before, he said that was the first time ever that he noted sewer gas was under pressure. We are not sure what that means.

We know that the next step is to investigate the vent stack. Do we need to call the city sewer people and explain to them the sewer gas is coming to the house "at an increased pressure"? Does this mean that there is a blockage in the house vent somewhere?

Please help, you plumbing gurus!

PS our plumber and the contractor have not given very helpful ideas so far except what has been tried already.

Follow-Up Postings:

RE: Sewer gas smell in the basement bathroom

We also just had one bathroom with a "sewer smell".

In our case, when the water was first turned on in the sink, there would be a blast of the foul odor. First I thought it was the water itself, but then I decided to catch the water in a pot - no smell then. But when I poured it down the drain, up came the smell. Aha, perhap ssome bacteria, etc down the drain. So I poured a bit of bleach down the drain and that took care of it.

Hope this helps solve your problem.

(BTW, if that wasn't the cause, my next step was to pour some bleach down the sink & tub overflow drains.)

RE: Sewer gas smell in the basement bathroom

Your thought of the vent stack is probably correct. City sewer folks probably can't help you, though, since the problem is on your side of the sewer connection. You'll need to cal a plumber/handyman if it's not a DIY job for you.
I would snake the vent stack from the roof. You'll need about 50' or so of snake to do this. Most houses have more than one vent, depending on the locations of the drains, I'd snake all of them.


BTW, I doubt it's the vent line, but to check, you might try to isolate the wall cavity that it's in from the drain below. Maybe you could plug around any opening with rags and stick a piece of one inch tubing up in there and smell the other end with your nose. Crazy, but hey, it just might work.

I once dealt with a bathroom that had a vent line that came apart since one joint wasn't glued. In that case it caused a ceiling leak when it rained. Do you have any signs of moisture in that wall?

RE: Sewer gas smell in the basement bathroom

Are you sure the shower actually has a trap? You'd hear bubbling if the gas was really flowing through a trap filled with water. A DIY shower by previous owner may have been installed incorrectly.

RE: Sewer gas smell in the basement bathroom

We have an older house (1920) with a basement bath added in the 60s or 70s. The shower and toilet are not vented. If we remodel this bath, we need to vent. Ergo, no remodel, as it is such a freaking hassle...

 o Post a Follow-Up

Please Note: Only registered members are able to post messages to this forum.

    If you are a member, please log in.

    If you aren't yet a member, join now!

Return to the Plumbing Forum

Information about Posting

  • You must be logged in to post a message. Once you are logged in, a posting window will appear at the bottom of the messages. If you are not a member, please register for an account.
  • Please review our Rules of Play before posting.
  • Posting is a two-step process. Once you have composed your message, you will be taken to the preview page. You will then have a chance to review your post, make changes and upload photos.
  • After posting your message, you may need to refresh the forum page in order to see it.
  • Before posting copyrighted material, please read about Copyright and Fair Use.
  • We have a strict no-advertising policy!
  • If you would like to practice posting or uploading photos, please visit our Test forum.
  • If you need assistance, please Contact Us and we will be happy to help.

Learn more about in-text links on this page here