How to Plumb a Sink

Changing a sink or installing a new one requires that you plumb the sink. If you're replacing the same number of handles on your faucet, either one or two, the task is not as daunting. The most challenging part is lining the plumbing to the sink waste pipe. If your drain lines up, then you're in luck. Otherwise, you have to make adjustments in the plumbing so it does. Plumbing a bathroom sink isn't that difficult, but it does take time. In this guide, the plumbing is copper and the pipes are PVC.

Things You'll Need

• Plastic pipe saw
• Pipe cutter or tube cutter
• PVC pipe
• Copper pipe
• Fittings for drain pipes
• Fittings for copper pipe
• Shutoff valves
• Supply lines
• PVC solvent cement
• Plumbers putty
• Torch
• Flux
• Emery cloth
• Solder
• Faucet
• Drain
• Putty knife
• Channel-lock pliers
• Teflon tape

Instructions

1. Turn off the water. Measure how far up the rough in pipes, the ones that extend through the floor from the main water supply, rise above the floor. Subtract this number from 20 inches. Cut the additional appropriate length so you can run the pipes 20 inches from the floor. You need to sweat on a dog-ear elbow to the water pipe if you don't already have the shutoffs. Once you use a board to stabilize the new fitting, you'll sweat a pipe onto the unattached end of the dog-ear and attach a shutoff using a compression fitting.

2. Find the local code regarding the length from the stack to the trap. Most allow a 1 1/2-inch diameter arm that extends 5 feet from the trap to the stack. Some places have a limit of 3 1/2 feet. Make a 2-inch stack vent for your waste pipe. This step is unnecessary if you're replacing the sink or simply moving around the plumbing. You need to make certain, however, that you keep the drain within the limit of code.

3. Extend the drain outward from the wall so the height is 19 inches on center. It also needs to be 8 inches from each of the two water pipes so it's between them in the center. Attach enough pipe to bring the drainpipe to the spot you'll attach the PVC P-trap.

4. Secure the faucet to the sink. Normally, there's a nut below where the handles insert. Before you put the threaded shank of the faucet into the holes in the sink, either outline the bottom of the faucet with plumbers putty or use the plastic seal that most faucets have in their kits. Thread the nuts onto the stems once you put them through the holes in the sink. Tighten the nuts to hold the faucet.

5. Put in the drain for the sink. Make a snake of plumbers putty and circle it around the opening. Then insert the drain. Slip on the nut underneath and tighten it.

6. Dry-fit the P-trap to the rest of the waste pipes. If you need to, include a slip-joint piece to extend it if the fit isn't tight. Tighten the pipe at the drain. If it fits properly, put PVC primer and cement onto both pipes where the P-trap fits to the wall plumbing and make your connection permanent. Use your hands to tighten it.

7. Connect the supply lines to the shutoff after you wrapped the threads with Teflon tape, and tighten it with a wrench. Put the opposite end into the opening for the faucet and wrap the threads. Use your hands to tighten it. Turn on the main water supply and check for leaks in the drain and water supply. Turn off the water if the leak is in the faucet or water supply. Retighten the connections and try again. If the leak is in the drain area, you don't need to shut off the water.