How To Replace Undermount Sink Without Removing Countertop

How To Replace Undermount Sink Without Removing Countertop

Replace an undermount sink without removing the countertop might seem like a daunting task, but with the right tools and a systematic approach, it’s a project you can tackle on your own. Whether you’re dealing with a damaged sink or simply updating your kitchen’s look, this guide will walk you through the process step-by-step. From preparing the workspace and disconnecting plumbing to installing and securing the new sink, we’ll cover everything you need to know. By following these instructions, you can achieve a seamless, professional-looking installation without the hassle and expense of removing your countertop. Get ready to transform your kitchen with minimal disruption and maximum satisfaction.

Tools and Materials You’ll Need

  • Replacement sink
  • Adjustable wrench
  • Screwdriver
  • Utility knife
  • Caulking gun and silicone sealant
  • Plumber’s putty
  • Bucket
  • Towels

Prepare the Area

First, clear out the space under your sink. Remove any stored items to give yourself room to work. Place a bucket under the sink to catch any water that might spill during the process. Lay down towels or rags to protect your cabinets and floor from any potential water damage or debris. Ensure you have adequate lighting to see all the plumbing connections clearly. This preparation will make the task more manageable and help prevent any unnecessary mess or damage.

Disconnect the Plumbing

Turn off the water supply to the sink. Open the faucet to drain any remaining water from the pipes. Use the adjustable wrench to disconnect the water supply lines and the drain pipe. Be prepared for some water to spill out, so have towels handy. Disconnect any garbage disposal or dishwasher connections if applicable. Make sure all connections are fully detached before proceeding.

Detach the Sink

Use a utility knife to cut through the old silicone sealant around the edge of the sink. Locate the mounting brackets underneath the countertop that hold the sink in place. Using a screwdriver, remove the screws from these brackets. Carefully lower the sink and remove it from underneath the countertop. If the sink is heavy, consider having someone assist you to prevent injury or damage to the countertop. Once the sink is removed, clean any remaining sealant or debris from the countertop to prepare for the new installation.

Clean the Area

With the old sink removed, scrape away any remaining silicone sealant or putty from the countertop using a putty knife or scraper. Make sure to remove all residue to ensure a smooth surface for the new sink installation. Clean the utility sink of the area thoroughly with a mild cleaner and a damp cloth, then dry it completely. This step is crucial for ensuring a secure and watertight fit for the new sink.

Install the New Sink

Apply a bead of plumber’s putty around the edge of the sink’s drain hole. Insert the drain assembly into the hole and tighten it from underneath, ensuring a snug fit. Next, apply a generous bead of silicone sealant around the edge of the new sink where it will contact the countertop. Carefully lift the new sink into place, aligning it properly. Press down firmly to ensure the sealant spreads evenly and creates a watertight bond.

Secure the Sink

Lift the new sink into place, ensuring it fits snugly against the underside of the countertop. Reattach the mounting brackets to secure the sink in place. Tighten the screws, but be careful not to overtighten, as this could damage the sink or countertop. Double-check that the sink is evenly aligned and securely fastened before proceeding.

Reconnect the Plumbing

Reconnect the water supply lines and the drain pipe. Ensure all connections are tight to prevent leaks. Reattach any additional plumbing fixtures, such as a garbage disposal or dishwasher connections if applicable. Turn on the water supply and check for any leaks. If everything is secure and no leaks are present, your new sink installation is nearly complete!

Finishing Touches

Apply a final bead of silicone sealant around the edge of the sink where it meets the countertop. Smooth the sealant with your finger or a caulking tool for a clean, professional finish. Allow the sealant to cure according to the manufacturer’s instructions before using the sink. This final step ensures a watertight seal and a polished look, completing your under-mount sink replacement without the need to remove the countertop.


Replace an undermount sink without removing the countertop is a manageable project that can refresh your kitchen or bathroom without the hassle of a full renovation. By following these detailed steps—preparing the area, disconnecting the plumbing, detaching the old sink, cleaning the space, installing and securing the new sink, reconnecting the plumbing, and applying finishing touches—you can achieve a professional-looking result. Patience and attention to detail are key to ensuring a successful installation. With your new sink securely in place, you’ll enjoy a fresh, updated look and the satisfaction of a DIY job well done.

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