I want to re-plumb the PEX water lines + drain supply line in my laundry room. The back wall of the laundry is an exterior wall with standard fiberglass insulation. Currently, the water lines to the utility sink and washer come up through the floor, out sideways through an interior wall. The washer drains into my utility sink. The utility sink drains into a PVC drain pipe that is vented.

Question, is the following plan good/bad/horrible?

  1. Install an outlet box into the back exterior wall, affixed to a wall stud, allowing at least 30" of height for the drain pipe.
  2. Run PVC drain pipe behind the wall, then out the wall, and tie into P trap underneath the utility sink.
  3. Run PEX plumbing up from basement, behind the wall, and connect to the outlet box.
  4. Turn off water main, cut existing washer water supply lines in basement, connect to new PEX plumbing with Sharkbite push-in connectors.
  5. Patch the holes.

Laundry Room Overview Sink underneath

  • That plan sounds fine. The only issue I see in your second photo is that there is a lot of light hitting that PEX. UV breaks down PEX and makes it brittle over time so hopefully that's not direct sunlight in your picture.
    – MonkeyZeus
    Jul 1, 2020 at 20:07
  • Direct sun or high kelvin lamps anything above 4K will age most plastics.
    – Ed Beal
    Jul 1, 2020 at 20:10
  • The light is from my kitchen area. I cut a hole in the drywall opposite the laundry room to see what the drain pipe/water lines looked like. It will be covered up after this project.
    – Chris
    Jul 2, 2020 at 1:55

1 Answer 1


I would say this would be much better than the current surface mount of the pex. It will look better and less chance of damaging the lines.

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