Mystery open kitchen drain behind wall - need advice about plugging it

[ahappymoron]

My kitchen sink drain became blocked and, while unblocking it with a plunger and lots of water, I saw the dirty water leak from behind drywall about 6 feet away from sink. I had previously noticed a smell from the same area and dampness on the drywall.

So I cut open the drywall and find an open pipe coming up from the floor, and the dirty water was coming out of that pipe. see picture attached.

I think this is wrong, probably against code, and I think I should put a screw on cap to close this pipe - but I'm guessing.

Please will someone give me their thoughts on this. Why is it like this, what's the purpose?

 

[Gasmk1]

should it have been linked into the vent ?

 

[ahappymoron]

My uneducated guess is 'no', because it would mean that when the plumbing gets blocked (like now), it would plug the vent pipe. But, I really don't know.

 

[SimonG]

From the look of things its North American.
Not a vent either.
Solvent weld straight connector and then a screwed plug glued into that.

 

[ahappymoron]

Yup, U. S. of A ... and "solvent weld straight connector and then a screwed plug glued into that." makes perfect sense.

Thanks!