Using above ground piping for toilet install in basement.
#1

I am currently remodeling my basement and plan to put in a bathroom with toilet and sink. I have the 4" main sewer line coming from the mainfloor down into basement with a height of 23" to the floor and the 4" pipe that gradually slopes downward and around one end of the basement and out to the septic tank. At the lowest point which is the exit to the septic tank the pipe is 10" from floor. Is there a way to put a toilet in using the existing piping? The piping is visible and obstruction free. I was told by one contractor that it would be possible, just build a platform for the toilet to sit on. Is there a minimum or maximum height that the piping has to be in order for the commode to flush properly and not back up and make a mess in the basement? Thanks in advance, Ken
#2
Bigripper1, Welcome to the DIY Forums.
You CAN do this. Gonna be a big step up to the toilet platform (probably 2 steps). You also need a vent or the toilet trap will get sucked out when other fixtures are used. Pitch for the discharge pipe from the toilet should be 1/4" per foot. As long as the toilet is above the drain, it should not back up unless the main line to the septic clogs and backs up to the heigth of the toilet rim. . Good luck.
You CAN do this. Gonna be a big step up to the toilet platform (probably 2 steps). You also need a vent or the toilet trap will get sucked out when other fixtures are used. Pitch for the discharge pipe from the toilet should be 1/4" per foot. As long as the toilet is above the drain, it should not back up unless the main line to the septic clogs and backs up to the heigth of the toilet rim. . Good luck.
#3
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I would use an ejector pump and pit. To me building a platform is "cheesy" 
The platform would need to be high enough so that the pipe will have the required slope (I think 1/8" for a 4" pipe, but 1/4" is recommended), and the elbow for the toilet. Don't also forget the required vent for the toilet.
A sump pit would be more work, but much cleaner.

The platform would need to be high enough so that the pipe will have the required slope (I think 1/8" for a 4" pipe, but 1/4" is recommended), and the elbow for the toilet. Don't also forget the required vent for the toilet.
A sump pit would be more work, but much cleaner.
#5
... as high as you can go without hitting your head when standing.
Do you have that much room?
You'll like a gravity system better in the long run.
You want a short run to where you tap in otherwise, you have vent issues to deal with.
Other than that, six inches above the other pipe should do.
Use 3" PVC. Pre-assemble the new fittings first to determine minimum clearances. Then build the platform.
Do you have that much room?
You'll like a gravity system better in the long run.
You want a short run to where you tap in otherwise, you have vent issues to deal with.
Other than that, six inches above the other pipe should do.
Use 3" PVC. Pre-assemble the new fittings first to determine minimum clearances. Then build the platform.