How to Replace a Drain Trap

1-2 hours

Learn how to replace the P-trap underneath your bathroom or kitchen sink

Replace a Drain Trap

The curved pieces of drain pipe underneath your sink, commonly referred to as p-traps, do a lot of dirty work. Over time they leak, become corroded or get plugged with years of accumulated soap and grease. When replacing a P-trap, you should use the same type of trap you remove.

Traps are made from ABS (black), PVC (white) or brass (either chrome-plated or natural colored). Traps come in 1 1/4 inch (standard bathroom sink) or 1 1/2 inch (standard kitchen sink) inside diameter sizes. Be sure to check so you get the right size replacement at your local store.

In this guide we’ll show you how to replace a P-trap in a few easy-to-follow steps.


Remove the old drain pipe
Remove the old drain pipe - Replace Drain Trap

Remove the old drain assembly from the top down. Use the pliers to unscrew any stubborn slip nuts. Remember the drain trap (the U-shaped bend) will have a small amount of standing water so have your bucket or bag handy. To make sizing the new drain pieces easier, keep the old drain parts for now.

Attach new tailpiece
Attach new tailpiece - Replace Drain Trap

• For the kitchen: Put the tailpiece washer into the flared end of the tailpiece, then attach the tailpiece by screwing the slip nut onto the sink strainer.
• For the bathroom: The sink drain starts as a tailpiece and may reach the P-trap without additional parts. If not, add a tailpiece to make up the distance, cutting it to the needed length.

Add a T-fitting (if necessary)
Add a T-fitting (if necessary) - Replace Drain Trap

• If you're working on a sink with two basins, use a continuous waste T-fitting to join the tailpieces.
• Attach the fitting with slip washers and nuts. Make sure the beveled sides of washers face the threaded portion of the pipes.
• Applying pipe lubricant on the slip washer will ease installation and ensure a tight fit.

Attach the trap arm
Attach the trap arm - Replace Drain Trap

Attach the trap arm to the drain stub-out, using a slip nut and washer. Remember to keep the beveled side of the washer facing the threaded drain stub-out. If necessary, the trap arm can be cut to fit with a hacksaw.

Connect trap bend to the trap arm
Connect trap bend to the trap arm - Replace Drain Trap

Attach the trap bend to the trap arm, using slip nuts and washers. The beveled side of the washers should face the trap bend. Tighten all the nuts with a pair of slip joint pliers. Never use Teflon tape on white plastic pipe threads and fittings. Be careful not to over-tighten and crack the slip nuts.