I can feel slight airflow and occasionally some odor coming up from the basement floor drain. My wife and I moved to Pittsburgh and are in an old house. I had to have it snaked a couple of months ago due to it flowing over and the plumber explained that in this city there is a P trap between the sewer line exiting your house and the main sewer under the street. The P trap was clogged and had to be snaked. There is another access point to that P trap that he didn't seal real well. Could air flow between those two drains account for the occasional odor and/or draft coming up from the large drain? There's more of a draft when a tub is emptied or the washing machine is draining. Or does this indicate a crack in a vent pipe?

Any info would be appreciated. Thanks

A P trap is directly below a sink but we know what you mean. Is the floor drain itself trapped, it should be and I'd add a bucket of water to the drain to re-establish the trap. I have never worked in PA so don't know if what he said it true or baloney, leaning toward baloney. Do you see traps under your sinks, those are P traps so why would you also need a whole house trap, anybody from PA can step in a correct me. If " he didn't seal real well" then call him back, his connections must all be air tight and he darn well knows that. Do you see your vent stack starting in the basement and continuing up and out your roof line? Check it for cracks too.

I have added water down the main floor drain but that doesn't have any effect.
He told me that the house traps exist between the home and the mains to prevent rats from coming straight up the line into the house. Said that Pittsburgh was one of the only cities that employed them and it was a very old practice.
I know water is moving through that trap and out to the sewer because I can hear it if I remove the cover to that particular access.
As far as checking for cracks in the vent pipes, I read that sometimes they use a "smoke test" to do that. Is there a way to check ones' self before getting a pro involved?

A pro would do a much better job than most DIYers because he has the means to do a smoke test but visual inspection is also easy and free. We have an east coast plumber here and he will see this post and maybe know something about PA. plumbing. Traps prevent sewer gas from baking up not rats. I am really thinking this guy is making up stuff as fast as I can type. Bad wax rings under toilets are also frequent sources of sewer gas in the home but I think you said you smell gas right at the floor drain, right? This is what a floor drain cut-away SHOULD look like Sioux Chief 800-APK One Piece Floor Drain Assembly

Hi Guys...

PA is somewhat known for having HOUSETRAPS only with relief vents and a house vent. In this case, the fixtures would NOT have individual PTRAPS.

In my area, they used to plumb homes lkike this, but over time plumbing codes changed and we were required to install the individual fixture traps. We are required to remove the house trap ONLY if repiping the main drain pipe.

The odor you are smelling is probably just a result of the inner drain pipe smelling. It is why we finally transitioned over to the individual traps... ;)

You could try using a drain deodorizer or even better, a TRAP GUARD may hel in the floor drain... click on link below for more info.

Design Specifications : SureSeal Inline Waterless Floor Drain Trap Sealer

Questions? Let us know, OK?

Mark

PS: As Ballengerb1 stated, the cap at the house trap needs to be air-tight... have plumber return and fix that, for sure!

PA has lots of house traps. They do NOT eliminate the need for the individual fixture traps. At least I don't know how you would pass inspection without them.

As to the OP's problem, I've seen that several times in floor drains. The old iron ones would rust and the screw that held the upper half of the trap in place would disintegrate. Then someone would misplace that piece and you had a soil line vent right in your basement. I attached a picture (pardon the quick and dirty CAD work) of what I'm talking about. I bet you are missing that dome shaped piece attached to the grate.

Hope this isn't doubled, it's the first time I tried this.

Hi EP...

It's not an issue of passing inspection... it is an issue of existing work that goes back so far that at that time they only required the house trap (and relief vent, etc.). Here, they had yet to figure out that even the dirty pipes inside the home were giving off bad odors so every house was piped as pictured above.

In terms of today, of course, I am sure they require the individual fixture traps, for sure!

Hopefully, Tomebone will pop back in and see what we have presented and will give us some feedback on his setup... :)

Thanks... Mark

Man, I never even heard of a house that relied solely on the house trap, but I know of plenty of modern ones that have the 2 cleanouts out in the yard. I must be a spring chicken. :^D

We were born back in the day of wooden drain pipes.