How to Install a Laundry Room Utility Sink

Assess Your Layout

Begin by deciding exactly where the new sink will sit. Ideally, position it as close to existing water supply and drain lines as possible — this minimizes the amount of new piping you will need to run. Use a stud finder to locate the framing behind the wall so you know where you can and cannot route pipes. Mark the desired sink centerline on the wall, then measure outward to confirm there is adequate clearance for the basin, faucet handles, and any adjacent appliances such as your washing machine.

Take note of the rough-in dimensions specified by your sink manufacturer. These tell you the exact heights and lateral positions for supply stubs and drain openings. Getting this right now prevents frustrating rework later.

Remove or Open the Drywall

Once the layout is set, you will need access to the stud cavities behind the finish wall. Using a utility knife, score and remove a section of drywall large enough to expose the area between studs where your supply and drain connections will be made. If existing plumbing stubs are already present, you may only need a modest opening. If you are running new lines from a remote source, plan a larger cutout — or multiple smaller access holes along the route — so you can work comfortably.

Keep the drywall pieces intact if possible; they can be trimmed and reinstalled later as patches. Set aside screws and dust for easy cleanup.

Drill Through the Studs

If your supply and drain lines need to pass horizontally through wall studs, use an appropriately sized drill bit — typically a ¾-inch or 1-inch spade bit for supply lines, and a 1¾-inch or 2-inch hole saw for drain pipe. Always drill in the center of the stud to preserve structural integrity, and never notch or bore through a stud where the remaining wood would be too thin to carry its load. Local code specifies maximum bore sizes relative to stud width, so double-check before you drill.

Tap Into the Water Supply Lines

Shut off the main water supply (or the nearest upstream valves) and open a faucet downstream to relieve pressure. Cut into the existing hot and cold lines at the point closest to your new sink location. Install tee fittings and run new branch lines — copper, PEX, or CPVC, depending on what your local code permits and what matches the rest of your system — over to the sink location. Terminate each branch with a shut-off valve mounted at the correct height on the wall.

If you are soldering copper, work carefully around wood framing and use a flame shield. PEX with crimp or push-fit connections is faster and eliminates the fire risk entirely.

Tap Into the Drain and Vent System

Depending on your existing plumbing layout, you may be able to tie the new sink drain into a nearby standpipe or existing drain line. The sink's P-trap must be properly vented to prevent siphoning — either through a direct connection to a vent stack or by installing an air admittance valve (AAV), if your jurisdiction allows one. Maintain the correct slope on horizontal drain runs (typically ¼ inch of drop per foot) so wastewater flows reliably toward the main drain.

Use PVC or ABS fittings consistent with the rest of your drain system, and make sure every cemented joint is fully seated and allowed to cure before testing.

Install the Faucet and Supply Lines on the Sink

Before mounting the sink to the wall or cabinet, it is much easier to install the faucet while the basin is still on a flat work surface. Feed the faucet through the pre-drilled mounting holes, secure it with the provided hardware from underneath, and hand-tighten the supply hose connections. Apply a thin bead of plumber's putty or the gasket supplied with the faucet to create a watertight seal against the sink deck.

Mount the Utility Sink

Lift the sink into its final position and secure it according to the manufacturer's instructions. Wall-mounted utility sinks typically hang on a steel bracket that is lag-bolted into the studs; freestanding models may include legs or a cabinet base. Use a level to confirm the basin is sitting evenly — a slightly off-level sink will cause water to pool on one side. Tighten all mounting fasteners firmly but avoid over-torquing, which could crack a composite or porcelain basin.

Connect the Drain Assembly

Attach the basket strainer or drain fitting to the sink's drain hole from above, applying plumber's putty underneath the flange. From below, thread on the lock nut and tighten until snug. Connect the tailpiece to the strainer, then attach the P-trap. The trap's outlet arm should slide into the drain stub coming out of the wall. Hand-tighten all slip-joint nuts first, then snug them with channel-lock pliers — just tight enough to seal, not so tight that you crack the plastic fittings.

Hook Up the Water Supply

Connect the braided supply hoses from the faucet to the shut-off valves on the wall. Hand-tighten first, then give each connection a final quarter-turn with a wrench. Slowly open the shut-off valves and check for drips at every connection point — the valves themselves, the hose fittings at the wall, and the hose fittings at the faucet. Let the water run for a minute, then inspect the drain connections for leaks as well.

Add the Sink Faucet and Trap

With everything connected and verified leak-free, install any remaining accessories — a soap dispenser, a sprayer hose, or a drain stopper. Run both hot and cold water at full pressure for several minutes, checking underneath periodically. If you spot any moisture, tighten the offending fitting slightly. Once you are satisfied that every joint is dry, apply a thin line of silicone caulk where the sink meets the wall to prevent splashed water from running behind the basin.

Restore the Drywall

Patch the drywall openings you created earlier. For small holes, use the saved cutout pieces backed by scrap wood or drywall clips. For larger sections, cut a new piece of drywall to fit, screw it to the framing, and finish with joint tape and compound. After the compound dries, sand smooth and apply primer and paint to match the surrounding wall. Your laundry room is now fully finished with a brand-new utility sink.