How to Install a Laundry Room Sink

What You'll Need
PVC primer and glue
Drain fittings
PEX tubing
PEX to existing pluming fittings
PEX to sink fixture fittings
PEX tool (rent)
Sink faucet
Utility sink
Platform material
Channel lock pliers
Shut off valves
PEX straps

Installing a laundry room sink then enjoying its utility will leave you wondering why you didn’t do it sooner. Take these steps to laundry room convenience:

Step 1 – Install the Drain Fitting

Turn off the water at the house main. You’ll be cutting into drainpipe and water supply lines. Inform your family or your plans. You don’t want anyone flushing.

The simplest application will see the drainpipe located behind your proposed laundry tub location but you may need to plumb to your washer area to gain access to a drain pipe. Take photographs of your existing condition then print copies for reference at your DIY or hardware store. Ask for help if you are unsure which fittings to purchase.

Install the PVC drain fitting by holding it next to the drainpipe then mark the drainpipe so that you may remove a large enough section to install the fitting. The PVC fitting has a built-in coupling at all ends. Cut so that these couplings will fully seat onto the drainpipe.

Place a bucket under the drain before you cut to catch any water that remains in the pipe. Use a hacksaw or carpenter’s saw to remove the existing drainpipe section. Eliminate any burrs from your cut.

Apply ample amounts of PVC primer and then glue to the fitting and drainpipe. Install the fitting so that that the branch for the utility tub points to the tub’s location and is at a slight up-angle. (Water flows downhill so everything you do must keep this law in mind.)

Step 2 – Install the Vent System

Dry fit the vent system first (cut then assemble the pieces without glue to insure fit) by assembling the necessary fittings to tie into the vent stack. Using the fitting as a guide, cut into the vent stack then glue the assembly together as you did for the drain.

Step 3 – Assemble the Trap

Set the sink in place then take measurements for the trap. Cut and then dry fit the assembly as above to ensure proper fit.

Because water only flows downhill you may find that you will need to install a platform for your utility tub so that the sink’s drain runs down ¼ inch for every 1 foot of length. You may build this from wood then cover with vinyl flooring or tile but a more utilitarian solution would be solid concrete blocks, bricks or pavers.

Glue the trap into place.

Step 4 – Install the Faucet

Install the faucet into the utility tub then use channel lock pliers to tighten the nuts from under the sink.

Step 5 – Set the Tub into Place

Set the tub into place then insert the sink’s chrome tailpiece (the drain at the sink’s bottom) into the trap and then fasten the tailpipe’s compression nut to the drain system trap with channel lock pliers.

Step 6 – The Water Supply

Cut then install PEX compression fittings appropriate to your existing plumbing into the hot and cold water supply lines. Using red for hot and blue for cold, run PEX tubing to the utility tub. Follow the PEX manufacturer’s directions to install the PEX tubing to the existing water line “T” first, and then to the sink’s faucet shut-off valves last. Strap the PEX as necessary for support.

From the shut-off valves connect the sink’s faucet.

Step 7 – Test

Turn on the water to test for leaks in both the water supply and drain systems.