My son bought a 100 year old house with a small bathroom. It has been renovated within the last 6 years but the previous owners installed a cabinet-mounted sink that takes up a lot of room. He would like to replace it with a lower-profile pedestal sink. I have been asked to do the job!

The problem is the drain and water supplies come out of the floor about 4" from the finished wall (pictures attached). The floor is nicely tiled under the cabinet and it is out of the budget/skill set to tear up the floor and reroute the plumbing below the floor level. The current plumbing relies on an Air Admittance Valve (AAV) and I will be forced to do that in the new configuration.

I was thinking of routing the drains in one of 3 ways. Either 90 degree or 45 degree elbows and take the drain into the wall. Run the vent up to an AAV that would be situated behind the mirror so it can be serviced. I can make a cover for the plumbing easier if I use 90 degree elbows. The other is to run the drain along the wall and put the AAV underneath the sink. I'm not actually sure I have enough room to get the P-trap in, though.

I'm leaning towards A or B which will be a lot more work but seems more appropriate in the long run.

Current Plumbing 1

Current Plumbing 2

Proposed drains

  • I don't think there is any way to make a pedestal sink, they make cabinet style vanities as narrow as 18" maybe consider that route?
    – redlude97
    Commented Jan 6, 2022 at 0:54
  • what about putting the angled part as high as possible
    – jsotola
    Commented Jan 6, 2022 at 2:32

2 Answers 2


So long as you use drain swept 90's (not sharp 90's) A is just fine. Probably should add a cleanout on the second 90, actually. Which might mean a sanitary Tee with a cleanout plug in the top port.

Going with a smaller cabinet base seems simpler from afar. I've lived with a few pedestal sinks and would never put one in, as a result.

Where I needed seriously compact, I have gone with small wall-hanging sinks.

  • My son is really set on a pedestal; I have one that can be returned and have an idea on a small cabinet as a back up. Will demo first and then mock it up to look for the sweet spot of (my) efforts and effect. Thanks to all
    – drjrt
    Commented Jan 6, 2022 at 12:49

Looks like B is the only option.

Using swept 90 degree elbows it is 9" from the outside edges of the top and bottom fittings. The pipe is 4" from the finished wall and 1/2" for the wall, I really only can afford 6-1/2" to make the two 90's and stay within the studded wall. Won't make it.

There isn't enough room to get a P-trap in if I try to keep the plumbing on the outside of the finished wall.

So, to get the plumbing into the wall I will need to use the 45's.

Was thinking of putting the clean-out between the 45's as compared to the upright section in the wall, is that OK?

Picture is me mocking it up at home. enter image description here

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