Do-it-yourself kitchen sink plumbing

Moving the kitchen sink to a different location during a remodelling project or adding a new kitchen area to your home means plumbing for the sink. There are three parts to the plumbing job: the water supply, drain and vent systems. They work together to form the plumbing system throughout your home.


The sink waste water goes through a P-trap before it ties into the rest of the drain system. The P-trap has to be vented. You can use 1 1/2-inch pipe for this. Vent the P-trap in the wall behind the sink where it ties into a vertical pipe with a waste-tee. The vent goes up, the drain goes down.

Plan to run the supply water pipe for hot and cold up through the floor if you can, especially in cold climates. This prevents the pipes from freezing. Hot is always on the left and cold on the right.

If you have to drill holes in wall studs or floor joists for pipes, reinforce them with steel plates made for plumbing work.

Visit your local building department or code enforcement department to obtain plan approval before starting work. Permits are usually required and inspections will have to be done prior to closing up walls and making final connections.

Supply Lines

Run the pipe into the cabinet from the floor or bring it in from the wall behind the sink base cabinet. Rough the pipes in and cap them before the sink base is installed. Finish the supply plumbing after the sink base is installed. Turn the water off, cut off the caps and install an air chamber. Shut off the valve for each supply line.

Use solder connections on copper pipes for the supply line valves. If they don't leak from the start, they will never leak. The valves themselves can be multi-turn or quarter-turn valves. Quarter-turn valves are easy to turn off in a hurry, and there's never any question which way to turn them.

Connect the supply pipes to the faucet with flexible braided supply lines. Use large pliers to tighten the connections only if they leak.


The drain from the sink should travel horizontally to the wall with a slight drop. At the wall it connects to the vertical drainpipe and goes down into the drain system. Use a vent pipe that goes straight up from this connection and ties into the secondary or main vent, either in the attic or between floors.

Use schedule 40 PVC or ABS plastic according to local codes. Select drain fittings for drainpipe connections. They have smoother and longer turns to facilitate faster movement of the water. Other fittings may cost a few cents less, but ultimately won't save you much if the inspector makes you take them out and replace them.

Make the final connection to the sink drain tailpiece after the sink is installed. Use a brass drain kit with compression fittings. The cheap plastic ones will eventually leak.

Vent Pipe

Vent pipes let air into your drain system and exhaust sewer gas through a main pipe that exits the house through the roof. A drain that isn't vented won't drain properly. Connect the drain through a P-trap and horizontal pipe that enters the wall behind the sink. Using a drain-tee, make the connection to the main or secondary vent in the attic or between floors.

Use fittings labelled DWV for Drain-Waste-Vent. All fitting connections require the use of primer and glue. Inspectors usually look for the primer, especially on PVC installations.