That is an exterior wall. That pipe vents outside of my house, about 5 inches above ground level.

The big pipe is, what I perceive to be, the vent. It goes to a mesh vent on the outside of my house.

Oh you meant the other end, in the slab. Not sure, but it is right above the main sewer line and cleanouts, so I still suspect it to be the sewer vent.

>but I am planning on using the space behind this mess, building shelves against the wall

A cabinet won't work for me, need shelves against the wall to the right of the drain.

Yeah great idea, and definitely need the space to be accessible.

Great idea.. but I am planning on using the space behind this mess, building shelves against the wall. Unfortunately we don't have an attic or basement so the garage is the only storage we have. Need to make the most of the space. Thanks for your reply.

I think this is how my house was originally set up, unfortunately. There are 2 cleanout caps at the bottom of the hole, 1 facing the house and 1 facing the street. I cannot bury the cleanouts unfortunately.

There isn't a threaded plug outside, just a vent unfortunately. There are 2 cleanout caps in the hole - 1 that faces the house and 1 that faces the street. Would be great to eliminate this as it is really unsightly, but lots of good suggestions in this thread. Thanks for your reply.