How to Replace the Drain Trap on a Sink


Replacing the drain trap under your sink is an important plumbing task that helps keep your drains flowing properly. The drain trap is the u-shaped piece of pipe located directly under the sink drain. Over time, it can become clogged with hair, soap scum, and other debris, or the seal can wear out. Replacing the drain trap is an affordable DIY project that can extend the life of your plumbing system.

In this comprehensive guide, we will walk you through the entire process of drain trap replacement, from picking the right parts and tools to the step-by-step installation. Whether you’re a DIY novice or seasoned home plumber, this guide will equip you with the key information and tips you need to safely and successfully replace a sink drain trap. Let’s get started!

What You’ll Need

  • Adjustable wrench
  • Channel type pliers
  • Bucket
  • Flashlight
  • Safety goggles
  • Teflon tape or pipe thread sealant
  • Replacement drain trap kit

Optional supplies:

  • Basin wrench
  • Cordless drill

Step-by-Step Guide

Turn Off Water Supply

The first step is to locate the shutoff valves for the hot and cold water lines under the sink and turn them clockwise to shut off the water supply. This prevents water from spraying out when you disconnect the drain trap.

Place Bucket Under Trap

Put a bucket under the trap to catch any water still in the pipes when you disconnect it. Have some towels ready to soak up any spills.

Loosen Drain Pipes

Use your adjustable wrench to loosen the slip nuts connecting the trap to the sink tailpiece and drain arm or P-trap extension. Turn counterclockwise to loosen. You may need to hold the trap steady with your other hand to prevent twisting.

Remove Trap

Once the nuts are detached, carefully maneuver the trap out from under the sink. Make sure to keep it level to avoid spilling water.

Clean Connections

Inspect the tailpiece, extension arm, and trap connection points. Use a wire brush or steel wool to remove any grime or buildup. This ensures a tight seal with the new trap.

Apply Thread Sealant

Wrap Teflon tape clockwise around the threads on the trap arm and tailpiece. You can also apply pipe thread sealant. This prevents leaks. Don’t use too much tape or sealant.

Position New Trap

Align the new trap into place, inserting the tailpiece end into the drain arm side and the drain arm end into the tailpiece side. The curve should face down.

Hand Tighten Nuts

Hand tighten the slip nuts to hold the trap in place. You want it to be snug but still adjustable.

Adjust Trap

Position the trap so there is just enough room between the bottom curve and the sink basin. If needed, loosen the nuts to adjust alignment.

Tighten Nuts

Once aligned, finish tightening the nuts with your adjustable wrench. Turn clockwise to tighten. Be careful not to overtighten.

Turn On Water

Turn the shutoff valves counterclockwise to turn the hot and cold water back on.

Check for Leaks

Run water through the drain and carefully inspect all connections for leaks. Tighten nuts further if needed.

And that’s it! You’ve successfully replaced the drain trap under your sink. Taking the time to follow these steps helps ensure a smooth installation and prevents problems down the road.


How do I know when to replace my drain trap?

Replace your drain trap if it is leaking, corroded, cracked, misaligned, or clogged with gunk and debris that cannot be cleaned out. A faulty trap can cause water to leak and lead to bigger problems. Replacing it at the first signs of wear is recommended.

What are drain traps made of?

Most modern drain traps are made of plastic, such as PVC, ABS, or CPVC. Older traps may be made of metal, such as brass, steel, or iron. Plastic is lighter and easier to work with.

What size drain trap do I need?

Standard sink drain trap sizes are 1-1/4 or 1-1/2 inches. Measure the inside diameter of your tailpiece and drain arm to determine the right size replacement. Most traps have slip joint connections for 1-1/4 or 1-1/2 inch pipes.

Can I replace just part of the trap?

It is best to replace the entire trap assembly. The curved section and slip nut seals wear out over time. Replacing the whole trap ensures optimal drainage and leak prevention.

How do I prevent trap leaks?

  • Ensure slip joint nuts are tightened properly
  • Use thread sealant on male threaded fittings
  • Align trap so there is no strain on joints
  • Hand tighten connections first before final tightening
  • Avoid overtightening nuts

Is it OK to reuse old slip nuts and washers?

Slip nut and washer seals wear out over time. It is advisable to use the new hardware that comes with the replacement trap kit. This guarantees optimal sealing.

How can I remove stuck slip nuts?

Penetrating oil can help loosen stuck slip nuts. Turn or wiggle the nut as the oil penetrates. Pliers may help grip and turn frozen nuts. Cutting the nut off is a last resort if needed.

Why does my new trap leak even though I tightened it?

  • The trap may be misaligned and strained. Loosen and realign.
  • Debris could be on seal surfaces; disassemble, clean, and reassemble.
  • Damaged slip nut, bolt, or washer. Replace hardware.
  • Hairline crack in trap. A new trap is needed.

What do I do if the new trap doesn’t fit my drain pipes?

You may need to replace the adjacent drain arm and tailpiece with the appropriate diameters and connection types to fit the new trap. Use adapters if needed.


While it may seem intimidating, replacing a sink drain trap is a straightforward project that even novice DIYers can tackle. Following the steps in this guide will ensure you get it done efficiently and safely. Paying close attention to proper alignment, tightening, and leak testing sets you up for plumbing success. For stubborn installations, don’t hesitate to call in a professional plumber. Investing in quality parts and taking your time leads to a drain trap that will perform optimally for years to come.

How to Replace the Drain Trap on a Sink: A Step-by-Step DIY Guide

Replacing a faulty or corroded drain trap under the kitchen or bathroom sink is a common DIY plumbing task. With the right tools and a little know-how, you can remove the old trap and install a new one in less than an hour.

Follow this step-by-step guide to properly replace your sink drain trap.

Getting Prepared

Before starting the project, gather the necessary equipment:

  • Adjustable wrench
  • Pipe wrench (may be needed for stubborn nuts)
  • Small bucket
  • Old rags or towels
  • Flashlight
  • Safety goggles
  • Replacement drain trap kit
  • Teflon tape

Turn off the water supply lines and place a bucket under the trap to catch any water still in the pipes.

Removing the Old Trap

To remove the existing drain trap:

  1. Loosen the slip nuts at both ends of the trap using your adjustable wrench. Turn counterclockwise to loosen the nuts.
  2. Once detached, carefully maneuver the old trap out from under the sink. Place it in your bucket.
  3. Inspect the tailpiece and drain arm for any grime buildup. Clean with a wire brush if needed.
  4. Also check the sink drain basket and remove any debris clogging the drain.

The old trap and slip nuts can now be discarded.

Installing the New Trap

Follow these steps to install the new replacement trap:

  1. Wrap Teflon tape around the threads on the tailpiece and drain arm. This helps create a watertight seal.
  2. Position the new trap by aligning the tailpiece side with the drain arm. The curve should face down.
  3. Hand tighten the slip nuts over the Teflon tape onto both sides of the trap.
  4. Adjust the trap as needed to get proper alignment under the sink.
  5. Tighten the slip nuts with your wrench. Be careful not to overtighten.
  6. Slowly turn on the water supply and check for leaks. Tighten any connections further if needed.

That’s all there is to it! With your shiny new trap installed, your sink drainage will be restored. Be sure to clean the trap regularly to prevent future clogs. Replacing traps every 5-10 years is advisable to maintain proper plumbing.

Helpful Tips for Drain Trap Replacement

  • Turn off main water supply for entire house if separate hot/cold shutoffs are not reachable
  • Place a towel under joints to catch drips when disassembling
  • Soak stubborn slip nuts with penetrating oil before loosening
  • Avoid overtightening slip nuts as this can crack the plastic trap
  • Use pipe wrench for better grip and leverage on stubborn connections
  • Adjust trap alignment before final tightening to prevent strain
  • Run water for several minutes to flush out any debris and check for leaks
  • Consider replacing adjacent tailpiece/drain arm if corroded or incorrectly sized

Replacing a sink drain trap may seem like an intimidating task, but having the right tools and following these straightforward steps will ensure plumbing success. Investing in a quality trap and taking the time to properly install it will provide you with years of clog-free drainage.

Questions and Answers About Replacing Sink Drain Traps

Replacing the drain trap under your sink is an important plumbing maintenance task. Here are answers to some frequently asked questions about choosing, removing, and installing sink drain traps:

How do I know when I need to replace my drain trap?

Signs it’s time to replace the trap include water leaking from joints, corroded or cracked sections, frequent clogs, a misaligned trap, or a foul odor coming from the drain. A worn-out trap can cause major plumbing headaches, so replace at the first signs of failure.

What type of trap do I need?

Most sinks use a 1-1/2 inch P-trap. Measure the inside dimensions of the tailpiece and drain arm to ensure compatibility, or bring the old trap to the hardware store. Traps are available in plastic or chrome-plated metal.

What tools will I need?

Basic tools include an adjustable wrench, Teflon tape, a bucket, rag, flashlight, and safety goggles. Useful optional tools are a pipe wrench, hacksaw, and basin wrench.

How do I remove the old trap?

Loosen the slip nuts at both ends with wrenches and unscrew the joints by hand or with wrenches. Remove the trap, catching any water in the bucket. Clean slip nut seats and pipe ends of buildup.

Any tips for installing the new trap?

  • Wrap threads in Teflon tape
  • Hand tighten connections before wrench tightening
  • Position trap so it aligns properly under the sink
  • Tighten slip nuts firmly but not excessively
  • Run water and inspect carefully for leaks

Why might my newly installed trap still leak?

The nuts may not be tight enough, the trap is misaligned or strained, debris is interfering with the seal, or hardware is damaged. Disassemble, realign, clean, and inspect for cracks.

Can I replace just part of the trap?

It’s best to install a completely new trap. The curved section and washers wear out over time. Replacing the whole trap gives the most reliable results.

How can I prevent leaks with the new trap?

Careful alignment, hand tightening connections before using your wrench, not overtightening nuts, and keeping sealing surfaces clean all help prevent leaks with the new trap. High-quality parts are also important.

How often should I replace the trap?

Normal lifespan for a sink drain trap is 5-10 years. Replace sooner if you notice any signs of failure. Preventive maintenance helps avoid major clogs or leaks down the road.

Replacing a faulty sink drain trap is a straightforward DIY plumbing project. Following proper procedures for removal and installation will ensure your new trap provides maximum drainage for years of leak-free performance.


Replacing the drain trap under your sink is an essential maintenance task that helps keep water flowing freely down the drain. While it may seem intimidating at first, any DIYer can master this project with the help of this step-by-step guide. The key steps include disconnecting the old trap, cleaning the pipe connections, installing the new trap with properly tightened slip nuts, and testing for leaks.

Taking the time to gather the right tools and materials, following the procedures detailed here, and paying close attention to trap alignment and tightening at all joints will ensure success. Investing in a quality trap and completing this replacement regularly will provide you with exceptional drainage and prevent messy, costly plumbing issues. With the steps outlined here, you can tackle drain trap replacement with confidence.