Most of the time a sink will fit perfectly in a precut countertop opening, but test fit the sink and check that it sets level.

Apply plumber's putty around the sink's drain hole and seat the strainer assembly. Flip the sink upside down, tighten the drain nut and "tailpipe" piece.

Flip the sink upright and install the faucet, valves, and handles. Tighten down these items and hook up the water lines to a tee fitting.

You can also hook up the water lines coming into the valves and avoid doing that once the sink is set. Set a "self-rimming" sink in the hole and fasten any included mounting clamps underneath it. Run a bead of clear-drying caulk around the rim.

If the sink isn't self-rimming, run a bead of plumber's putty on the bottom of the lip and caulk the opening to keep water out. Seat the sink and tighten any clamps.

Remove any rags or cap blocking the drain stub and glue on a threaded adapter to the stub. Screw on a trap to the adapter threads and sink drain.

Screw on water supply lines (if you haven't already) and attach them to the shut-offs. Use a "two-headed" shut-off if you're also going to connect to a dishwasher.

Run some water down the drain to block sewer gases, and check each line and drain joints for leaks.

Hanging Garbage Disposers

The garbage disposer is normally installed with the sink. However, connect the supply lines to the faucet first, so you don't have to work around the disposer once it's in.

A special strainer and mounting assembly usually come with the disposer or sink. Attach the assembly with a snap ring and secure it with its included fasteners.
Hang the disposer on the mounting assembly and line up its drain hole to face the other sink's drain. Attach the discharge tube to the disposer's housing.

Fit the drain tube into a tee that connects to the other sink drain and the trap. Tighten those connections. Then connect the sink trap to the waste pipe.

NOTE: Most disposers have an inlet that connects to the dishwasher drain. We'll cover that connection in the dishwasher section.

Hooking Up Dishwashers

While positioning the dishwasher, feed its flexible drain hose under the sink. Get the unit it as level possible and securing it in place.

Fit a hose clamp over the pipe end and attach it to the dishwasher's waste discharge outlet. Clamp an adapter fitting on the pipe's other end and attach it to the disposer's inlet.

This way, the dishwasher's waste water and debris will run through the disposer, then the drain system; which will prevent clogged lines.

Loop the drain hose high up under the sink so if there's a clog in the sink drain, it won't immediately run down into the dishwasher. Some local codes may require additional measures to prevent this.

Run a copper hot water line to the dishwasher's connection (in our case, a threaded angle adapter). Run the other end to the two-headed water shut-off. Briefly run the dishwasher through its cycles and check the connections for leaks.