Basement Bath Rough-In for Sewage Ejection

[Carlos Cabrera]

I had my builder install a basement bath rough-in when I bought my house a few years ago. I just recently have gotten the urge to start planning my basement for finishing, so I’m trying to figure out how this plumbing will work.

The drain stubs are 3″ Sch 30 up through the concrete floor. The shower drain will be capped and unused (and sunken into the concrete) as it is basically in front of the electrical service panel and unusable. The sewage basin has a 2″ discharge opening, and a threaded opening in the lid for the vent pipe. There is a vent stack stub (1.25″) tucked up near the first level subfloor above the basin.

I worried about not having individual fixture vents, but was told by the plumber that did my rough-in that I only need to connect the vent from the basin lid to the vent stub that he installed – no other vent lines required. I suppose the sink and toilet have adequate venting as long as the water level in the basin doesn’t block much of the inlet pipe into the basin. This would mean that the tether switch for the pump would have to turn on at a level lower than the inlet pipe, right? Or does this not matter much?

I have two other questions regarding this system. First, would the vent line from the lid simply get adapted down to 1.25″ pipe and connected to the vent stub? Or should 2″ vent pipe be run up as high as possible before downsizing the pipe?

Lastly, the discharge line will have to connect to the 3″ drain line. That drain line begins near this sewage basin, but there is a vertical toilet drain above that then bends into this horizontal drain. What types of rules need to be followed for connecting the discharge line to the main drain line? I would think connecting downstream of the toilet drain would be advised – is there a minimum distance downstream? When the connection is made to the main drain, should the new port in the wye for the discharge line face up, or face the side, or does it matter?

These questions will determine the basic location and directions of the piping, which I will want to be concealed in soffits and/or closets. Thanks for your help.

[Retired plbg1Participant]

First thing is all the fix. in the basement have to be vented and run through the roof are con. into existing vent on first fl. at 42″ high.You should have 2″ on the sump but if Plbg. left a smaller pipe then reduce it to fit that size, you cannot con. your fix vent into a sump vent it has to be seperate.

[Author]

Posts