Plumbing question - swapping a toilet and a shower

I’ve got a 3/4 bath in my house, with the toilet sitting next to the shower. Both back up against the same wall.

Because of the layout of the room, I’d really love to swap the location of the 2. I figure that the water lines in is no big deal. Run some additional hot water pipe and away we go.

What about the waste pipes? I know nothing about what kind of piping arrangements are needed for toilets or showers. Is this an easy swap, or am I looking at pretty much rebuilding everything in order to do this?

You are in for some pretty serious work.

You’re right that water pipes are easy to relocate. Drains are a *lot *harder. If you’re lucky, once you pull up the floor, you’ll be able to “simply” shorten the toilet’s drain and move the floor flange straight along the existing line. If you need to extend the line or turn a corner, well, the job just got harder. What makes it hard is that toilet drains are usually cast iron - cutting and joining the stuff is in the realm of “very advanced do-it-yourself” or “call a professional” to do. Newer homes may use PVC, which is more DIY-friendly, but it’s not been commonly used except for the past few years, and even then, it depends on your particular state or county’s building and plumbing codes.

There may be structural concerns as well - those big cast iron pipes can’t just be passed through a hole drilled in a floor joist - if you need to cut joists, you may want to consult with an architecht before you cut too far and the floor suddenly grows in size as the walls move apart.

It’s impossible to answer the question without seeing the layout. If the shower is close to the waste stack then the answer is yes it can be done easily. If you have to cut into a floor joist for the toilet sewer pipe then the answer is probably not given the width of most joists. If it’s on the first floor and you have a basement then I’d say it wouldn’t be much of a problem at all as long as you don’t mind a pipe hanging low. If it’s on the second floor then another option is to enclose a low hanging pipe in the ceiling below.

Whatever you do, take advantage of long radius curves for your drain line. It makes all the difference in the world.

Hasn’t PVC been used for about 20 years?

Anyway, as others have said, It could be very hard. The toilet drain is biger in diameter than the shower. So, you can’t just hook up the toilet to the shower line. It will need to be reconfigured. And as Magiver said take advantage of long radius (sweep) curves for elbows.

I missed this. No, it’s not really advanced. You cut the cast iron with a sawzall and use a rubber joint made for the task. I did this in my house and there were no problems involved. I thought I would need to rent one of those cast iron cutters but with the right blade I sliced right through the cast iron. I used a cutting blade called “the torch”.

In my case, I had no choice as the cast iron was eaten up by acid. When the toilet was originally installed the sewer line did not have a slope to it. I was relieved when it all went as planned.

Since this job involves destroying the floor covering then it is quite feasible to make the changes given the location of the floor joists to the sewer stack. A patch will have to be made over the old toilet hole but that will be covered by the shower stall.

The above replies assume you have a conventional wood floor, and access to it from below.
If your’s is a slab foundation house, figure on serious money to cut new channels for the waste (toilet, aka “water closet” or “closet” - as in “closet flange” and “closet bolts”) and drain (shower) lines.
Do you have either a basement or a crawl space under the house, or is this on a floor above the first?

Yes, a slab means you’ll have to rent a concrete saw. Not sure of the connection but it’s not too major. I’d imagine its the same connection I described above (rubber connector). My BIL put a complete bathroom in his basement and I don’t remember any huge problems with the process. I would expect the finish work(ceiling, flooring) to take more time than the sewer lines. If it’s a basement job then this would be a good time to install a stopper valve in the line to prevent backflow from the street.

Well, you could always build a box and put the shower about six inches higher than the original floor. We did that when we converted a bathroom & laundry room into two bathrooms. We installed two new box showers. We made a custom drain line which comes up from the old bathtub drain and splits into a “Y” shape. Each shower drains into one leg of the “Y”.

We also set a toilet on the old washing machine drain. It all works fabulously, as long as you remember to step up when getting in the shower.

Since I usually read your user name as MacGyver, this was quite the apt username/post combo! :cool:

Thankfully, this bathroom is on the second floor of a split level house, with the laundry room below it. The laundry room ceiling doesn’t have to be pretty.

We’ve already had to replace the floor drain of this shower, due to stupid construction by the previous owners. It was cast iron, sandwiched between and through the floor joists. As Magiver suggested, we cut the pipe with a sawzall and replaced the end with with PVC.

So the shower drainpipe and the toilet drainpipe are different sizes, and not interchangeable. Blah. As for the wastestack. We haven’t actually seen it yet. I can guess where it is. Assuming they didn’t put it into the outside wall, and it’s centered behind the toilet, this would involve moving the toilet by about 4’ along the wall behind it.

Assuming the floor joists connect to the wall that has the waste stack in it then you can run the toilet line into the wall, and then to the stack. The shower drain will tie into this with an adapter. Or, as you stated, you don’t care about the ceiling beneath it you can drop both drains down, and then over to the stack. That would be reallly easy to do.