I started to get a smell in the downstairs bathroom and after ruling out the wax seal on the toilet it is coming from the sink drain. We are in a split level so technically its in the basement.

Strangely there is no P-Trap, just a drain that goes into the wall and I assume straight into the sewer line as the drain doesn't come out on the other side (a garage is on the other side of the wall).

Is there a reason for not having a trap?

The main question: How do I install one. I am quite handy and have no problems working with PVC but wanted to get advice on how I disconnect the copper (is it copper?) drain and what I would use to go Copper -->PVC (links to home depot welcome!).

I am assuming i use a blowtorch to melt any solder but want to check first as I don't usually work with copper. If it was a pressurized line I would call a plumber but I'm confident with guidance I can add the trap.

Sink Drain

1 Answer 1


What size is that copper? You can get plastic p-trap kits in 1-1/2" and 1-1/4", and these can be easily connected to your copper via slip ring compression fittings. Basically they consist of a nut with a cone-shaped plastic washer, which when compressed by the nut squeezes against the (copper) pipe to create a seal. Usually these are only on the sink side of things and the wall side has glued-on plastic but you can use the compression fittings on both ends.

Here is a 1-1/2" Plastic p-trap

If you want to solder, a better solution than using a compression ring on the wall side would be to sweat on a copper x female adapter, followed by a male PVC adapter and a PVC trap adapter. Better yet if you can find one, just use a brass copper trap adapter like the following:

enter image description here

A less desirable but acceptable solution would be to use a fernco fitting to go from the copper to PVC, and then you can avoid soldering.

  • That looks pretty straight forward so far - I have watched videos on sweating/soldering and I may use this as an excuse to give it a try. Am I right that I just need to warm up the joint at the wall to get it apart?
    – user19246
    Feb 25, 2014 at 15:40
  • I wouldn't say warm it up, you'll have to get it pretty hot to melt the solder. Have water and wet rags ready, you'll want to quench the pipe after soldering. It would probably be easier for you to just cut the pipe off right after the coupling by the wall and then solder the adapter on. When heating the new fitting remember that the solder will be drawn towards the heat. Obviously try not to point the torch at the wall!
    – Ethereal
    Feb 25, 2014 at 15:45
  • I will see if I have enough room to get a pipe cutter in there
    – user19246
    Feb 25, 2014 at 15:50
  • You can also just use a hacksaw, it might be easier considering the proximity to the wall and the goobers on the pipe.
    – Ethereal
    Feb 27, 2014 at 14:19
  • FYI I didn't have a pipe cutter so I tried a hacksaw to cut off a drain pipe but had trouble because of the tight quarters. What worked for me was an oscillating tool with a flush-cut blade.
    – rob
    Dec 6, 2014 at 19:16

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