Does this constitute an S-trap? I don’t believe so but I am not certain. Thanks!

Appears to be a “P” trap since the horizontal drain line appears to be longer than 6 inches. You would have to measure it to be certain. I am seeing a lot of plumbers fix old “S” traps by extending the horizontal run these days.

Unless there is a AAV where it turns down, it looks likes it nothing more than a modified S-trap. The key is venting…not necessarily distance. Even with AAV you need to check that they are permitted in your area.

Oh yeah, when inspecting AAV / Studor vent they should be 4 inches above the weir of the trap. This can sometimes be problematic with deep bowls of kitchen sinks…I have come across this a couple times…usually with renovations.

This is in a townhouse and it wasn’t possible to see the plumbing from underneath since it has a finished basement. Thanks to both of you for the input. Much appreciated.

It could be worse:D

Bruce, does the piping go back into the wall or down into the floor.
It looks like it may go back to a wall where I suspect its vented…if that’s the case then your simply looking at double trapping…blockage issues and trapped gases.

This is one of the reasons I never refer to handymen to do jobs that should be done by professionals. We see this allot in remodeling jobs and DIY’s.


PS. Patrick, if you don’t see a studor vent /AAV under sink then you should recommend it be evaluated by a licensed plumbing contractor.
Even if he erroneously gives bad information, you are off the hook.

That look more like a “C” or “G” trap!!

Thanks, Jeff. Great advice!