How to Install a Sink

Here are basic instructions on how to install a sink - a do-it-yourself project you can master!

DIY kitchen sink installation is best done with a top-mount style sink. Though under-mount sinks have become supremely popular, the top-mount is less expensive and much easier to install yourself.

Top mounts come in more styles and colors and, unlike under mounts, can be easily replaced by a homeowner.

The following top-mount techniques to install a kitchen sink include:

  • Cutting the hole in the countertop
  • Mounting the sink
  • Hooking up plumbing
  • Removing the old sink

How to Install a Sink - Cutting the Countertop


Most new sinks come with a template, but if yours doesn't, here's the best way to cut the countertop hole for your sink.

  • Flip the sink over and position it where you want it.
  • Trace around the edge with a pencil.
  • Remove the sink and measure the overhang - most are 1/2" to 1". Measure in from your line and mark the correct measurement on all four sides. Connect the marks with a straight-edge and freehand the curved corners.
  • Drill a starter hole with your drill, then cut along your line with a jigsaw.
  • Do a dry fit with your sink. You may have to shave a bit off to get the perfect fit.

How to Install a Sink - Mounting the Sink


Make it easy on yourself! Install all the bells and whistles first before actually installing the sink. This saves you the aggravation later of crawling under the sink to hook things up.

  • Install the faucet onto the sink and attach the flexible water lines. If you're re-using the old faucet, unscrew the two nuts around the water inlets, pull the faucet out of the old sink and install it in the new one.
  • Install the strainer. Be sure to apply plumber's putty around the drain lip before inserting the strainer body.
  • You can install the garbage disposal first, too (unless you have a very heavy cast-iron sink).
  • Run a bead of silicone caulk around the hole in the countertop and insert the sink into position. Don't use plumber's putty - it can discolor eventually and show around the edges.
  • Tighten the mounting clips from underneath...start with a clip on one side, then do a clip on the opposite side. This makes the sink settle equally on all sides into the sealant caulk.
  • Now apply a bead of silicone caulk all the way around the edge of the sink. Smooth with your finger to get a small, straight line.

How to Install a Sink - Hook Up the Plumbing


Kitchen sink plumbing is pretty simple - clean water comes in, drain water goes out.

Clean water comes in through hot and cold water pipes located under the sink area. These should each have a shut-off valve so you can turn of the water right there. If your home doesn't have this convenience, shut off the main water line to the house.

Drain water goes through a series of pipe formations under your sink that connect to and drain into the sewer line.

The ingenious little piece of pipe known as a P-trap is used to keep enough water in your drain pipe to block the smell of sewage.

Here's the typical plumbing set-up under a double-bowl kitchen sink, with a garbage disposal and dishwasher.

  • The blue line is cold water. It comes in and hooks to your faucet.
  • The red line is hot water. It comes in and splits in two directions - one to the faucet and one to the dishwasher.

The drain from your sink meets the drain from your garbage disposal (and the sink bowl on the right) with a T-fitting. Attached to the bottom of the T is the P-trap, and then piping from that goes into the drain pipe in the wall.

There's also a line from the dishwasher where the dishwasher drains water out through the disposal and down the drain.


How to Install a Sink - Removing the Old Sink


Removing an old sink and installing a same-size new one? You can normally re-use the plumbing that's there.

  • First, carefully score the caulk around the edge of the sink with a utility knife. NOTE: You may need to run a putty knife under the edge to loosen it. If you don't care about preserving the existing countertop, you can skip this step.
  • Most sinks have clips right under the countertop - either remove or loosen the screws, then turn the clips to the side to release the sink.
  • Turn off the breaker(s) for the dishwasher and garbage disposal. NOTE: TAPE A "DO NOT TOUCH!" SIGN ON THE BREAKER BOX!
  • Unplug or disconnect (if hardwired) the garbage disposal.
  • Place your bucket or pan underneath to catch water.
  • Disconnect the dishwasher drain line from the disposal. If there's no disposal, disconnect the dishwasher from the pipe.
  • Loosen the P-trap fitting all the way from the straight drain pipe just under the sink.
  • Disconnect the hot and cold lines from the shut-off valves and the hot line going to the dishwasher.
  • Lift out the sink with disposal, faucet and straight drain pipe still attached.

IMPORTANT! There's always the possibility of leaks - keep your water pan in place when you turn the water back on.

Once you make any adjustments needed, give it a minute and check again for leaks...when everything is perfect, remove the pan.

The basics of these instructions on how to install a sink can also be applied to other sinks such as bath or laundry.

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Thinking of remodeling?

Keep a notebook or scrapbook of notes, clippings and ideas.

Kitchen magazines are expensive - look through them in the grocery checkout line. If you see pix of a kitchen you really like, buy that magazine.

Stop in at home centers and pick up any free cabinet manufacturers' catalogs.