If you want to replace your bathroom undermount sink, you’ll have to remove the old unit first. The process is DIY, and anyone can do it. But you can mess up things if you don’t know how to go about it.

You first remove your sink plumbing assembly, disconnect the garbage disposal, let loose the screws, clips, or brackets holding your sink in place, and finally cut the silicone bond holding your sink to the countertop.

Here’s a detailed guide on how to remove undercount bathroom sink:

Remove an Undermount Bathroom Sink

Tools you’ll need:

  • Bucket
  • Rug
  • 2 x 4 lumber blocks
  • Screwdriver
  • Tongue and groove pliers
  • Hammer
  • Utility knife
  • Chisel
  • Heat gun

Step 1. Unhook the plumbing assembly from your current sink

You’ll first need to disconnect the p-trap assembly as part of making the sink easy to remove. Unscrew the end of the p-trap connecting to the drain tailpiece followed by the other end leading to the brain drain in your bathroom wall.

Unhook the plumbing

Carefully get out the p-trap and tip it into a bucket to empty the water inside. Now disassemble the rest of the p-trap assembly. Make sure you stuff a rag into the drainpipe opening (in the wall) to keep the sewage gases from entering your bathroom.

Step 2. Remove the drain assembly

With the p-trap assembly down, you should now unhook the drain assembly. Use pliers to loosen the drain assembly mounting nut, then unscrew and remove it with your hand.

Tap the strainer upward with a hammer to help loosen the putty seal. Now pull the drain assembly out of the sink drain opening from above.

Remove the drain

Step 3. Secure the sink

Before you detach your sink from the top, you’ll need to support it with 2×4 blocks and clamps. That is, you put a 2×4 across the sink opening, pass a bar clamp through your sink drain hole and hook it to the sink bottom and the 2×4.

But don’t make the clamping too tight; leave enough playroom for your sink so that you can easily pry it downward.

You can also place a 5-gallon bucket upside down and stack a few wood blocks on top of it to act as your support.

undercount bathroom sink

This support is especially essential for sinks made from heavy materials like cast iron, composite though it’s also advisable for use with other materials.

Good support will help prevent your sink from crashing to the floor and getting damaged or leaving dents on your bathroom floor.

Step 4. Remove the clips/screws/brackets

Different undermount sinks are held in place using screws, or clips, or brackets. Whatever you used for your sink, you’ll need to loosen it in this step to help you easily remove your sink.

Go under your sink and locate the anchoring clips holding your under-counter sink. Unscrew them with the help of a screwdriver.

If it’s your lucky day, your sink will disengage after removing these clips, and you’ll be able to get it out safely.

However, if your sink is held in place using a silicone sealant or other types of adhesive, you still have one more step to go.

Step 5. Unglue your sink

For this part, you’ll have to work from above your sink. Grab a sharp utility knife to cut through the adhesive by forcing it between your sink rim and the countertop.

If you placed your sink with silicone sealant, you’d have an easy time loosening it in just a few passes. You need to make that each cut gets more profound than the previous one.

If you’re dealing with a different adhesive such as construction adhesive or epoxy, a utility knife might not offer much help.

undercount bathroom sink

You’ll need a different approach for this problem:

Wedge a sharp chisel between the countertop and sink rim and gently tap it with a hammer. Be careful, so you don’t end up chipping your countertop material. This method will help you break the adhesive bond and separate the sink rim.

You can then put a pry bar in between the gap formed and pry the rim down to disengage your sink fully.


If the chisel method doesn’t work, the other option is to use a heat gun to soften this adhesive, after which you can try chipping, cutting, and prying to let free your sink.

Remove an Undermount Bathroom Sink

WARNING: Don’t use the oscillating tool to cut through the adhesive if your countertop is granite, quartz, or stone. The vibrations from this tool can easily crack your expensive countertop and force you to replace it with a new one. This tool is, however, safe for use with wood and other solid tops.


Removing an undermount sink in your bathroom to pave the way for a new sink is simple if you know how to do it correctly. The basic steps we have outlined here will help you quickly and safely remove your undermount sink. These steps apply to all the types of undermount sinks installed on various countertop materials.