How to Set Up Laundry Room Plumbing for a Washing Machine

Set up laundry room plumbing and install a washing machine with these expert tips.

Stacked washer and dryer

Kimberly Gavin

Project Overview
  • Total Time: 6 hours
  • Skill Level: Intermediate

You can't just buy a washing machine, bring it home, and hope it works. These dutiful appliances need to be hooked up to a water supply and draining system first.

In a basic laundry room, supply pipes branch off to provide hot and cold water to both the utility sink and the washing machine. The machine's drain hose clips to the side of the utility sink, which has a P-trap that connects to a house drain line.

To hook up a washing machine to hot and cold water and a drain, you'll need to install washing machine valves. These valves look like outdoor hose bibs but point straight down. The washing machine drain hose hooks to a standpipe or a sink, which has a P-trap that connects to a house drain line. The drain for either of these must slope down at a rate of 1/4 inch per running foot.

Many washing machines are self-leveling. Grab the machine by its control panel at the top rear, pull forward to slightly tilt the machine, and let it drop back solidly on all four feet. Adjust the front legs to make sure the machine is level in both directions.

What You'll Need

Equipment / Tools

  • Screwdriver
  • Groove-joint pliers
  • Propane torch
  • Hacksaw
  • Tubing cutter


  • Utility sink
  • Washing machine
  • Solder
  • Flux
  • PVC primer and glue
  • Trap
  • Pipe and fittings


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    Cut Pipe

    Shut off water to the supply pipes and drain the lines. To tap into a copper supply pipe, cut the pipe with a tubing cutter to install a tee fitting.

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    Set Tee Fitting

    Apply flux and sweat the tee fitting in place. If there is not enough movement in the pipe, a piece of pipe and a slip coupling (shown above) may be necessary. Or try a compression fitting.

  3. SCP_252_05.jpg

    Attach Stub Outs

    Add lengths of pipe to reach the laundry tub for the washing machine plumbing rough-in. This includes tees to run pipes to the washer. At the end of each supply pipe, sweat on a brass supply stub out. Anchor the stub outs to the wall with masonry screws.

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    Attach Hose Bibs

    Run copper lines to the washer. Add supply stub outs and anchor them to the wall with masonry screws. Apply pipe-thread tape and hand-twist each hose bib into its stub out, then tighten it with a wrench.

  5. Assemble Sink

    A plastic utility sink is inexpensive and easy to put together. Assemble the sink. Install stop valves on the sink stub outs. Install a faucet onto the sink and connect supply tubes to the stop valves.

    Editor's tip: Where there is no room for a utility sink, install a standpipe for the washer drain. The pipe must be large enough to insert the washing machine's drain hose into it, and the top must be above the machine's water level.

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    Run Pipes

    Tap into a drain line with a tee fitting and run a drainpipe (sloped at 1/4 inch per foot) to the sink. Glue an adapter to the pipe end and attach the trap.

  7. Install Washing Machine

    Set the washing machine in place and level it. Screw the machine's supply lines to the valves and tighten with pliers. Drape the drain hose over the side of the utility sink and clamp it firmly in place.

    Editor's tip: If your walls are not finished (the studs are exposed) or if you are able to run pipes through walls, you can install a washing machine supply box for a neater look. It controls hot and cold water with one valve and provides an outlet for a drain hose.

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