How to Install a Kitchen Sink

Make changes to an older kitchen with a kitchen sink upgrade.

kitchen sink with white subway tiles
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Project Overview
  • Working Time: 1 - 4 hrs
  • Total Time: 2 - 5 hrs
  • Skill Level: Intermediate
  • Estimated Cost: $200

The kitchen sink is a key work surface in the kitchen for rinsing vegetables, washing dishes, preparing cleaning solutions, and more. Given the importance of this plumbing fixture in most homes, it's necessary to ensure that the sink isn't cracked, chipped, rusted, or leaking. If your kitchen sink looks like it has seen better days or it has developed problems that make it difficult to use, like active leaks, then it may be time to consider replacing the sink.

If you are thinking about replacing your kitchen faucet, now is a great time, because the current faucet will need to be disconnected to remove the old sink, if the faucet is mounted on the sink instead of the countertop. Also, it should be noted that the water to the sink will need to be off during the installation, but if the sink doesn't have isolation valves for the hot and cold water lines, then you may need to shut the water off to the entire home. The replacement process is relatively straightforward, so experienced DIYers can learn how to install a kitchen sink in just a few hours with the right tools and supplies. Keep reading to discover how to upgrade your kitchen sink.

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Click Play to Learn the Difference Between Undermount and Drop-In Sinks

Before You Begin

Beginning a project like replacing your kitchen sink can easily become complicated, depending on the current set-up of your sink. Plan for the unexpected and prepare by measuring the sink, taking pictures (above and below the counter) of the set-up, and finding a replacement that perfectly matches the current space and plumbing needs. Determine whether you have a drop-in or undermount sink, what kind of countertop you have (and whether you will need to cut the countertop to install the new sink), if you need to replace any piping, and whether there are any other situations that may complicate the project. If in doubt, hire a professional to do this work for you.

What You'll Need

Equipment / Tools

  • Bucket
  • Channel locks
  • Utility knife
  • Bar clamp
  • Screwdriver
  • Wrench
  • Jigsaw
  • Caulking gun

Materials

  • 2x4 board
  • Sink clips
  • Silicone caulk
  • Plumbers putty

Instructions

  1. Turn off the Water Supply Valves

    Remove any items that you may have stored under the sink and look for the hot and cold water supply lines that feed the kitchen faucet. On these lines, there should be isolation valves that can be turned off to stop the flow of water to the faucet. Turn the hot and cold water off and turn the kitchen faucet on to drain any remaining water.

    If your kitchen faucet doesn't have isolation valves on the hot and cold water lines, then you will need to find the main shutoff valve that controls the flow of water into the home. This valve can be found where the main water line enters the home. Look in the basement or crawlspace to find this valve, but if you cannot locate it, you may need to contact your local water utility company or hire a plumber to shut the water down from outside the home.

  2. Disconnect the Supply and Drain Lines

    Use a set of channel locks to loosen the nut that connects the hot water line to the faucet, then repeat the process with the nut on the cold water line. The plumbing lines will still have some water remaining, so place a bucket under the sink and align it with the hot and cold water supply lines.

    Next, loosen the nuts that are securing the drainpipe and P-trap, then pull them apart and set them aside. Keep in mind that the drainpipes will likely drip, as well, so position the bucket appropriately before disconnecting the pipes. It's recommended to label any parts that you remove and put them in a safe location until reinstallation.

    The drain line for the dishwasher is typically connected to the drainpipe under the sink, so it will need to be disconnected to free the drainpipe and make more space under the sink to work.

    Tip

    At this point, make sure to turn off and unplug the garbage disposal if you have one. Follow the manufacturer's directions to safely remove the garbage disposal unit.

  3. Cut the Caulk Bordering the Sink

    In order to separate the kitchen sink from the countertop, you will need to use a utility knife to cut the caulk that is bordering the sink. Slide the blade under the lip of the sink, making sure that the blade is completely flat so that it doesn't cut into the countertop. Cut through the caulk that is currently acting as both a seal and an adhesive between the sink and the counter.

    If you have an undermount sink, then you will need a 2x4 board that is longer than the sink is wide. Place the board over the sink, then run a bar clamp through the drain, securing one end of the clamp to the 2x4 and the other end against the drain. Use a second clamp if you have a second drain to prevent the sink from falling when you cut through the caulking seal.

  4. Loosen or Detach the Clips Beneath the Sink

    The caulking isn't the only thing that holds the sink to the countertop, so you will need to crawl under the sink and find the sink clips along the edges of the sink. Use a screwdriver or a wrench to loosen the clips, allowing them to pivot. If the clips cannot pivot, then just detach them entirely.

    Keep any clips that are in good condition, but replace any sink clips that are showing signs of significant wear, like cracking, rusting, or severely diminished rigidity.

  5. Remove the Old Sink

    If you have a drop-in sink that sits on top of the counter, then it's a good idea to have one person pushing up on the sink from underneath and a second grabbing the sink from above. Put the old sink out of the way, so that it won't interfere with the installation of the new sink.

    If you have an undermount sink, then you will need to loosen the clamps that are securing the sink to the counter and lower it slowly. Slide the sink out of the under sink cabinet and put it aside.

    Warning

    Sinks are heavy. If you are not confident in your ability to remove the old sink or put the new sink in place, then make sure to get the help of a second person. Attempting to maneuver a bulky, heavy kitchen sink on your own can lead to injuries or damage to the countertop, water lines, drain lines, and the new kitchen sink.

  6. Insert and Caulk the New Sink

    Before securing the new sink to the countertop with caulking, try putting the sink into the hole left by the old sink to ensure that it fits properly. If it doesn't fit comfortably, then you may be able to trim part of the countertop with a jigsaw to help a larger sink fit better, but a smaller sink should be returned to the store and replaced with an appropriate product.

    Once you are certain that the sink fits properly, apply silicone caulk to the borders of the sink. For a drop-in sink, apply the caulk to the underside of the sink's perimeter, then lower it carefully into the hole and wipe away any excess caulk with a rag.

    An undermount sink will need to have the caulk applied to the top of the sink's perimeter. Slide the sink into the cabinet and lift it into place. You or a helper will need to hold the sink while the sink clips are used to secure it to the countertop. It's also a good idea to temporarily reinstall the 2x4 and bar clamps to ensure the caulk forms a tight seal between the sink and counter.

  7. Secure the Sink With Clips

    The sink clips need to be fastened in order to secure the sink to the countertop. While this process should be done during the previous step for undermount sinks, it can be completed afterward for drop-in sinks. Make sure to replace any rusted or severely worn sink clips to ensure that the new kitchen sink is properly supported on every side.

  8. Reinstall the Faucet and Water Supply Lines

    The process for reinstalling the faucet is the same, even if you are installing a new faucet. You will need to run the faucet lines through the sink, then secure the faucet to the sink with washers and nuts. For the best fit, you may need to have a second person hold the faucet in place while you tighten the nuts.

    Connect the hot and cold water supply lines to the faucet with your set of channel locks, but make sure that you don't turn the water on to the faucet because the water currently has nowhere to go except into the under sink cabinet.

  9. Install and Seal the Drain Strainer

    Apply plumber's putty to the underside of the drain strainer, ensuring that there are no gaps that could lead to future leaks. Press the strainer down into the drain, then slide the rubber drain strainer gasket and nut over the bottom of the strainer from underneath the sink. Secure the strainer to the sink by tightening the nut, then wipe away any excess plumber's putty that gets squeezed out from the sides of the drain.

  10. Reconnect the Drain Pipes and Appliances

    Realign and connect the drainpipe and P-trap to the new sink. Typically you can hand tighten plastic fittings, but you may need to use a set of channel locks to ensure that there are no leaks. At this point, if you have a garbage disposal or dishwasher, you will want to reconnect the drain lines for these appliances. Make sure to follow the manufacturer's guidelines for reinstalling the garbage disposal safely.

  11. Turn on the Water and Test for Leaks

    The last step in the process is to turn on the hot and cold water valves, restoring the flow of water to the faucet. Some air will be forced out of the faucet, so be prepared for it to spit and sputter for a couple of seconds before a constant flow of water returns. Leave the water running and check the faucet, water supply lines, drain lines, and drain strainer for any leaks. If there are no leaks, then turn off the water and clean up your tools and any other debris.

    Some leaks can be caused by loose fittings, so try tightening the fittings on the water supply and drain lines if there is a leak. If the leak persists, then you may need to replace the fittings. This can sometimes occur with older plumbing that hasn't been touched in years. Also, make sure to restore power to the garbage disposal, if this is applicable to your kitchen.