How to Install an Undermount Kitchen Sink: A Step-by-Step Guide

How To Install An Undermount Kitchen Sink

Are you tired of cleaning around and under your kitchen sink’s rim? An undermount kitchen sink could be the perfect solution for you. These sinks are installed beneath the countertop, giving your kitchen a sleek and modern look. In this guide, we’ll walk you through the steps to install an undermount kitchen sink.

Materials Needed for Installation

A properly installed undermount sink can prevent water damage and make cleaning up a breeze.
A properly installed undermount sink can prevent water damage and make cleaning up a breeze.

Before you begin, gather the necessary materials for the installation process. You’ll need:

  • Sink
  • Mounting hardware
  • Sealant
  • Tools (screwdriver, pliers, silicone gun, etc.)

When choosing a sink, make sure it fits the size of your countertop and cabinet. You can find undermount sinks in various materials, such as stainless steel, porcelain, or composite granite. The mounting hardware typically includes clips, brackets, and screws.

Sealant is an essential material to prevent water from seeping into the cabinet. Silicone sealant is recommended for its flexibility and durability. Make sure to choose a sealant that is compatible with your sink material.

Preparation for Installation

Before you start installing the sink, it’s crucial to prepare the countertop and cabinet. First, measure the sink’s size and the cutout area on the countertop. If necessary, cut the countertop to fit the sink. Use a jigsaw or circular saw to make the cutout, following the manufacturer’s instructions.

Installing the Sink

Once you’ve prepared the countertop and cabinet, it’s time to install the sink. Follow these steps:

  1. Attach the mounting brackets: Place the sink upside down on the countertop and attach the mounting brackets with screws. Make sure the brackets are level and securely attached to the sink.

  2. Apply sealant: Apply a generous amount of silicone sealant around the edge of the sink. This will help create a watertight seal and prevent water from leaking into the cabinet.

  3. Mount the sink: Carefully lower the sink into the cutout on the countertop. Make sure the sink is level and centered before applying pressure to the edges. Wipe away any excess sealant with a damp cloth.

  4. Let the sealant dry: Allow the sealant to dry for at least 24 hours before connecting the plumbing.

Connecting Plumbing

Now that the sink is installed, it’s time to connect the plumbing. Follow these steps:

  1. Connecting the drain: Install the drain assembly according to the manufacturer’s instructions. Apply plumber’s putty around the drain and insert it into the sink’s drain hole. Tighten the mounting nut from underneath the sink. Connect the drainpipe to the wall or floor drain.

  2. Installing the faucet: Install the faucet according to the manufacturer’s instructions. Insert the faucet through the sink’s mounting hole and tighten the mounting nut from underneath the sink. Connect the water supply lines to the faucet.

Before turning on the water, make sure all connections are tight and secure. Test the sink for leaks by running water and checking the drain and faucet connections. Congratulations, you’ve successfully installed an undermount kitchen sink!

Connecting Plumbing

Now that the sink is securely in place, you can connect the plumbing. First, install the drain assembly into the sink’s drain hole. You can use a plumber’s putty or silicone sealant to create a watertight seal. Then, connect the drain tailpiece to the P-trap, and finally, connect the P-trap to the main drain line. Tighten all connections with pliers, but be careful not to overtighten them.

Next, you can install the faucet. Follow the manufacturer’s instructions to attach the faucet to the sink. Typically, you’ll need to insert the faucet’s base through the countertop’s mounting hole, tighten the mounting hardware, and connect the water supply lines. Turn on the water supply and check for leaks.

Final Touches and Testing

With the plumbing and faucet installed, you’re almost finished. Secure the sink to the countertop with mounting clips, making sure the sink is level and flush with the countertop. Apply a bead of silicone sealant around the sink’s edge to seal it to the countertop.

Finally, test the sink for leaks and proper drainage. Fill the sink with water and let it drain. Check for any leaks in the drain or faucet connections. If everything looks good, congratulations, you’ve successfully installed an undermount kitchen sink!


Installing an undermount kitchen sink may seem daunting, but with the right tools and materials, it’s a manageable DIY project. By following the steps outlined in this guide, you can transform your kitchen and enjoy the benefits of a sleek and modern undermount sink. Remember, proper installation is crucial for preventing water damage and ensuring your sink lasts for years to come.

Dayne Williamson

I'm Dayne Williamson, and I love all things technology and finance. I started Napo News Online as a way to keep people up-to-date on the latest news in those industries, and I've loved every minute of it. I'm always looking for new ways to improve my site and help my readers, and I can't wait to see what the future holds.

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