How to Install a Kitchen Sink

1. Turn off the Water Supply Valves

   • Remove items stored under the sink and look for the hot and cold water supply lines that feed the kitchen faucet.
   • Turn off the hot and cold water isolation valves 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 for this valve. If you cannot locate it, 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.
   • 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. Put a bucket under the drainpipes since they will likely drip.
   • Label parts that you remove to help you easily reinstall them.
   • The drain line for the dishwasher is typically connected to the drainpipe under the sink. Disconnect it to free the drainpipe and make more workspace under the sink.

   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

   To separate the kitchen sink from the countertop, 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 to break the seal between the sink and counter.
   • If you have an undermount sink, then you will need a 2×4 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 2×4 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 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, have one person pushing up on the sink from underneath and a second grabbing the sink from above. Place the old sink out of the way.
   • If you have an undermount sink, 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. Measure the Countertop Opening

   • Measure the countertop opening for the new kitchen sink after removing the old 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 trim part of the countertop with a jigsaw to help a larger sink fit better. However, a smaller sink should be returned to the store and replaced with an appropriate product.

7. Insert and Caulk the New Sink

   • 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 2×4 and bar clamps to ensure the caulk forms a tight seal between the sink and counter.

8. Secure the Sink With Clips

   • The sink clips need to be fastened 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 proper support.

9. 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, 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.

10. 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.

11. Reconnect the Drainpipes 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.

12. 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 the leak persists, you may need to replace the fittings. This can sometimes occur with older plumbing that hasn’t been touched in years.
    • Also, restore power to the garbage disposal, if this applies to your kitchen.

When to Call a Professional

If you need to replace any piping, if there are any other situations that may complicate the project, or if you are in doubt about any aspect of this job, hire a professional to do this work for you. In addition, a farmhouse-style sink is a more intricate installation that may require a pro to handle.

Tips for Installing a Kitchen Sink

• Know the parts of a sink before attempting this project so you can follow the manufacturer’s installation instructions.
• Check to see if your plumbing is rusted and needs replacement before installing the sink.
• Check to see if your countertops have excessive water damage around the old rim or sink opening that may prevent the successful installation of a new kitchen sink.
• When connecting the new sink drain to the drainpipe, consider the materials you are attaching. You may have a plastic sink drain that needs to connect to a metal drainpipe, which may require a specific adapter or coupling. 

Cost to Replace a Kitchen Sink

If you opt to replace your kitchen sink yourself, you will only pay the price of the materials and tools. Kitchen sinks can range from a couple of hundred dollars to nearly $1,000 or more depending on manufacturer and style.

If you hire a professional plumber to replace a kitchen sink, it can cost between $216 and $642, which includes labor, but does not include the sink itself. However, this average depends on where you live, the type of sink, and the scope of the project (whether it includes new countertops), so it may be much less expensive or more costly than anticipated.