Hello. We recently purchased a house with a finished (insulated drywall over concrete block/painted concrete floor) basement, and on one side of the basement is a nicely finished but small (5' x 4') closet. In relation to the house, the back of this closet is the concrete wall that runs along the frontside of the house. There are 4 things inside this closet: (1) against the middle of the back wall, the water main & main shutoff, (2) in the upper left corner, the gas line comes in, then does a 90 degree turn and exits, (3) in the floor toward the back/right is a capped cleanout (the piping to the sewer runs under the basement floor, attached to city sewer), and (4) there is already electrical in the form of a light switch, an overhead light, and a working GFI outlet (why I'm not sure but there it is).

Now, a friend of mine came over the other day and said "man, you should stick a toilet and sink in here." Yes, it's small - but we measured and found that an airplane style bathroom could probably be pulled off. So that got me thinking and looking online, where I see all kinds of information about upflush stuff, but not much about issues when connecting below floor.

I should note that I would have a licensed plumber doing anything involving water or drains. I would just like to get a few thoughts up front so that I know if it's even worth my time bringing someone in.

My main questions are:

(1) Code wise, might it matter that the gas & water come in through this closet? My "McGuyver-wannabee" (aka you can help but you're not touching the plumbing) friend is telling me he could frame over them & add access panel for the main shutoff.

(2) Having the cleanout located in the floor would seem to be telling me that the main drain to the city sewer is running right under there somewhere - is this cleanout something that could work for or against me? Would I be leaving it alone, and have the plumber chop into the floor to add what is needed for the toilet/sink?

(3) The upstairs bathroom (there is just one on the first floor) is on the other side of the house, albeit directly across from this closet. Where the main stack & vent from that toilet go down into the concrete floor is about 20 feet from this closet. So I would presume a separate vent would also have to be installed in this new bathroom, correct?

Thank you for your thoughts

Do you want this powder room in your house? I would get 3 plumbers that gave a free estimate and tell them your idea-

So can I take that to mean you don't see any glaring problems with what I describe?

To answer your question: Yes, I want it, if there aren't any glaring issues that make the project more trouble/expense than it's worth - but do I need it? No. So I am at that point where if it can be done cheap enough ($3000?) without cutting corners but rather doing everything the right way then OK. If there is a code issue to deal with for example, like having to move where the gas comes in, or having to be more feet from the cleanout than I have room for proper operation/etc. then I would drop it in a second.

I wish I knew a plumber here (where I now live) I could trust - but personal experience has told me that there are plenty of hack contractors out there who will do anything you want, regardless of what might be the right way, resulting in problems down the road. That is why I thought I would start somewhere (like here) where I can at least feel confident that the person (like yourself) responding knows his stuff, has no vested interest in cutting corners to score a job, and might be able to pick out a glaring issue or two that I can address right up front.

Thanks

(1) Code wise, might it matter that the gas & water come in through this closet? My "McGuyver-wannabee" (aka you can help but you're not touching the plumbing) friend is telling me he could frame over them & add access panel for the main shutoff.

Check local codes to be sure. If you plan on platforming the addition most of the underground work can be done between the platform and the floor. If the cleanout can't be used The floor wiill have to be opened and a fitting cut in the main to pick up the toilet
The vanity will tie to the toilet drain and a vent will be run from the lavatory through the roof or revented back in the attic to a existing roof vent.

(2) Having the cleanout located in the floor would seem to be telling me that the main drain to the city sewer is running right under there somewhere - is this cleanout something that could work for or against me? Would I be leaving it alone, and have the plumber chop into the floor to add what is needed for the toilet/sink?

It depends on whether the cleanout tee's brought to grade or if it's buried and a raiser that can be connected to a toilet flange. Your plumber will have to determine if it's better to tie to the cleanout or cut in a fitting.

3) I would presume a separate vent would also have to be installed in this new bathroom, correct?

Correct, answered in #1.

Good luck, Tom

I don't think the whole project will come in under 3k. You got breaking concrete, running pvc and copper piping, patching concrete, walls, ac, fart fan, drywall, paint, flooring, permits, setting and buying fixtures, and a door.

Actually, it's already finished structure-wise, so walls, ceiling, paint, light, AC, GFI outlet, door already there. I'm just hoping ~3k can handle the toilet, sink, vent and exhaust. The permit isn't much here, and we actually have a toilet and pedestal sink from the redone bathroom upstairs. Appreciate all the answers to this - I'll check code & if OK I'll get the quotes, and then I guess we'll see where the $$'s fall. Seems nothing like this is ever as cheap as you'd like it to be.

Most Plumbing codes will require a minimum of 15" side clearance on both sides from the center of the water closet.