[Camelot_One]

I'm building a bathroom in my basement. Started with a builder installed rough-in, pipes run under the slab to the ejector pit. The pipes were all capped and glued when I started, so presumably there shouldn't be anything in them.

I installed the ejector pump and plumbing, and it is working perfectly. Installed the bathtub yesterday. It does drain, it just doesn't drain as fast as it fills. (1/2" pex in to the valve, roughly 50psi on the main line) Googling this only turns up solutions on clearing clogged drains, when you know it is draining slower than it was before. But this is my first experience with a basement bathtub. All of my other tubs here and in previous houses were on the second floor, with a long vertical drop. So I don't have a point of reference on what this one should be.

Am I just expecting too much from what I assume is a 1/4" per foot slope to the pit? Is there a guideline for drain speed, or a test I can perform to find out if it is draining like it should?

 

[Ghostmaker]

If you turn the shower on only does the tub build up water? Did you attach the bathroom vent?

 

[Camelot_One]

Yes, the vent is attached and unrestricted. I also snaked the drain line, and didn't find anything. It is possible the builder didn't maintain a proper slope under the slab, but I have no way to check that. (nor would I want to try to fix it)

I installed the shower head, and it does NOT back up in the tub. But it claims to be 2.5gpm MAX, so I'm not sure that is much of a test. I may see if I can find a higher flow shower head to test with. It is possible this slow drain only seems slow to me.

 

[Ghostmaker]

I wouldn't worry about it. The pipe may be back pitched only way to know for sure is a camera on a snake. Should have no standing water after the trap.