Replacing Wash Machine Outlet Box

I finally own my own home after many years (a split-level) and am working on sprucing up, repairs, etc. My first project is the laundry room on the lower floor, but I keep finding nasty surprises for such a small space. Most I've been able to fix (trim, spackling, etc.), but 2 have me just blown away.

I removed the ancient (and apparently leaking) wash machine and found a hole in the floor under the sheet linoleum. There was one rusty bolt sticking out. The depression is the size of a small salad plate and the bolt belongs to some corroded plug. What on earth is this? The washing machine drains by a hose into the outlet box in the wall, so what does this do?

Secondly, the outlet box is gunked up, discolored and has a small crack because the hotwater spigot was dripping and corroded. I can replace the spigot easily, but do I have to tear up the wall in order to replace the outlet box? Home Depot/Lowe's offer the same Oatey brand box, but it has brackets that are screwed into the beams behind the sheet rock. I don't want to tear out the wall if I don't have to, but my husband bought me a new, stacking washer/dryer set (Happy Birthday to Me! ). If I stack them where they fit, then the mystery hole and outlet box will be in full view. Is there anyway to replace it without tearing open the wall?

I really don't know what that bolt in the floor might be. It could be something used once to bolt down something, it doesn't sound like it is plumbing related, but it's hard to say for certain from the description. If it was mine and I was doing it, here's what I'd do. It may seem like more work that just patching what you have, but you very well just run into one problem after another and spend more time and money trying to fix the old than just tearing out and replacing what need replacing.

I'd cut out the floor around that bolt and find out what it is and what is under there. Since the floor has a depression, the subfloor is likely rotten and needs replacing anyway, so cut it out, deal with what's under it and go from there. You make too much to do about cutting into the drywall. Drywall patching is one of the simpliest things a home owner needs to be able to do. It's likely or at least possible that your standpipe and drain are just 1-1/2", but new washers need a 2" drain, so while everything is opened up, see that your drain is 2" all the way to where is joins a larger drainline and that it is properly trapped and vented. I'd put in a new outlet box with a single lever shutoff that cuts both hot and cold.

mysterious black hole

I cut the linoleum a bit more and found that the hole is perhaps some sort of drain. The corroded bolt was apparently part of a plug. Since this is the lower level, the hole is concrete and the surrounding ring is black metal. I found a new plug for it at the store. I guess I'll have to seal the linoleum. I'm hoping to put a decent looking cover on it for safety, as well as aesthetics. Any ideas as to what it's for?

Thanks for the heads-up about the 2" drain. I had no idea. I was really hoping to just pop something new in and finally get to painting and trimwork!

What size is the plug? If it's 4", I'd suspect it is a clean-out. If your washer drain is going into concrete, to put a 2" drain in you will have to chip out conrete to access the drain line. Note: you can not just stick a 2" pipe on the 1-1/2 pipe going into the drain. You can increase size but not decrease.

The plug for the floor drain is 1-1/2" with about a 4 inch metal collar.
The wash machine drains into pipe in the wall outlet box. There is a sewer pipe outlet 8 inches up the wall in the corner.

I'm beginning to think that the hole in the floor is a bit of a red herring. Our neighbor said that some things here weren't built to code. The house is 24 years old, don't know if that is useful info or not.

That's too small to be a clean out. It is not uncommon to find unorthodox things in older homes, and this would fit that description. Can you plug it so that the plug is completely below the floor level? Have you ascertained the size of the existing standpipe? It's possible that it is a 2". Otherwise you have to figure out how the get to the main drain with 2".

It's not flush with the floor. It sits down in a little bowl-shaped depression. I put a new, red plug in it. I've decided to let sleeping drains lie for now. Someday when I tile the floor in, I'll make some sort of fitted cover. I just don't have time or $$$ for it.

Right now there is rust coming out the bottom of the hot water heater. I don't know if I did something to it (I unplugged it while painting) or if that little black drain is really the portal to some sort of gremlin. We also had a leak in the leased water softener and the repairman shut it off. It's right next to the hot water heater....maybe that triggered off the hot water heater problem? or both? Should I hire an exorcist?