I have an unfinished basement and there are two sewer drains that go into the basement floor, on opposite sides of the basement, one for each ground floor bathroom. Along another wall and away from those drains, about 12" away from the wall, there is a pipe that comes about 3" out of the floor and has a 4" inside diameter and a screw on top. When I open it, I can see that it goes down and quickly bends away toward the wall (presumably out of the house)... it doesn't look like it joins up with the other sewer drains but I can't be sure. My

My question is: Is this a rough in that I can use for toilet/sink/shower drain, should I add a bathroom to the basement? Or is this some other sort of drain that should not be used for waste? How do I know or find out?

The 4" pipe picks up the toilet and there should be another 2" pipe somewhere for either a shower or a tub. The vanity will be picked up from a 2" pipe that will set inside a wall and will run up and reconnect to a roof vent in your attic. The entire bathroom group will be vented by this pipe. Here's a typical bathroom rough in. Good luck, Tom

Thanks for the response... there is no 2" pipe, just the 4". I just don't want to find out the hard way after I install a toilet that it actually drains to the street rather than the sewer line... I want to make sure this 4" pipe is meant for sewer. Any other thoughts?

Look around for a 14" square of cement that looks a little different from the rest of the pour. Sometimes the cement man will skim cement over a tub dap-out. If you see a patch of cement like that a hammer will break it out. Are there no other pipes coming out of the pour? Cheers, Tom

Speed is right on about the drain config. I had to search for my tub drain and sink drain/vent. If you take a hammer and tap on the slab near the wall on either side of the 4" pipe you may be able to find a "hollow spot" that could be the 2" sink drain/vent. If you are near a corner, work your way around the walls 5' or so on either side of the 4" stub.

The shower drain is likely near the wall as well, but could be out in the slab field anywhere from 36"-72".

Don't be shy about smacking the slab, you can always patch prior to your flooring install.

Also, while you're poking around, take a look in you unfinished basement ceiling and see if you can find a capped 2" pipe. It may be labeled future vent or something like that. If you find it that will make venting you new bathroom much easier. It may also help narrow down where your drain pipes are hidden. (they could be directly below the FV or very nearby... )

Excellent guys, thanks for the info. I've since poked around more and found that this is actually where other lines drain to.. looks like this is the last exit out of the house and agreed it is a toilet drain, though it is fairly clean. I'll look for a vent line and hollow spot. Thanks!

435 studio raised good points.

If you fail to find any other pipes in the floor or ceiling then you may simply have a clean out there in the floor... ;)

If this is a bathroom rough in you will definitely find, at a minimum, another 2" pipe somewhere close by.

Mark

Mark makes a good point also, If there are no 2" this could very well be a clean out. Although why the plumber didn't take it down to grade and install a clean out cover we'll never know. Cheers, Tom

Excellent info guys... if this is actually a clean out, can I still install toilet/sink/shower to it?

Thanks...

You sure can...

You can break out the concrete floor and install a wye fitting into the drain line to pick up the bathroom drainage.

You will also need to plan on running a 2" vent into an other 2" vent upstairs... you connect into the existing 2" or larger vent at a minmum of 42" off the finish floor. You could also run the 2" vent up and into the attic space where you can connect into a 2" or larger vent or penetrate the roof.

Any questions just let us know.

Mark


PS: There are also alternatives available that do not require breaking into the concrete floor, but they are usually not used when gravity drainage is available. You can check on 1 alternative at Saniflo macerating and gray water pumping systems