Plumbing – How to rearrange this plumbing to drain correctly

drainlaundryold-houseplumbing

So here's some plumbing in my house (not done by me):

This was before I sealed everything up behind drywall. The drain is actually used for a Cat Genie, our laundry is in another room.

Now we're having an issue where the drain is not draining quickly enough, sending gross water from the fancy flushing litter box onto the floor.

I've got an endoscopic camera down to the wet trap and didn't see anything amiss, but before I tear into the drywall, I was hoping someone could tell me — does this plumbing job look acceptable? Do you think my problem is here or downstream?

The venting you see is into the wall — this is on the first floor, getting a vent all the way to the roof in this 80 year old house would be a Herculean task.

Any pointers appreciated — I do ok with electrical, but other than decent skills with PVC, plumbing isn't my area of expertise.

Best Answer

I'd say the standpipe is a bit short, though I think 24" is minimum code. If the p-trap is clear, then possible issues:

  • there's a clog further downstream
  • the cat toilet is simply expelling too much water too fast
  • the vent stack is plugged

It's not a great fix, but one potential solution is to install a wash basin and connect that to the p-trap instead. Then have the cat toilet dump into the sink. That way the wash basin can completely fill and slowly drain.

Related Topic