Sink removal fundamentals are not difficult to master. Anyone with a basic knowledge of tools and the ability to lift up to 20 pounds vertically can pull out an old sink in an afternoon without much trouble. This article will give the basics of sink removal, assuming that the sink to be removed is either top or flush mounted.
Turning Off the Water Supply
Turn off any valves between the sink and the wall. If the plumbing runs straight into the wall or floor, you may have to turn off the main water supply for the house. Once you have shut off the water, open the hot and cold valves on the sink and allow them to drain.
Disconnecting Water Lines
Disconnect the hot and cold water lines. You will not usually need to mark the lines, but if your sink is not standard (hot on the left), then it may be a good idea to mark which one is which. If this is a permanent sink removal, you can save time by simply cutting the lines.
Removing the Trap
Remove the P-trap by unscrewing the large connectors on either side of it. Have a small bucket or pan in place to catch any spillage. Stuff a rag into the drain opening to prevent odors and gases from becoming overpowering.
Removing or Releasing Clips
If they are readily available, unfasten the clips which hold the sink in place. If they are not easy to reach, you can break these clips off to save time. A new sink will come with its own clips, so you don't need to worry about breaking these. If the sink is mounted to the wall, removing the clips may release it completely. Either shore it up against falling, or have a helper support it while you release the clips. Also, wall-mount sinks sometimes slide down over a locking edge; in this case, you must remove the sink by sliding it vertically up the face of the wall.
Breaking the Seal
Using a utility knife, cut and remove the caulking which runs around the edge of the sink. If the sink is built into a counter-top, the seal may be along the underside of the counter. When you have removed this seal, the sink should move freely in the opening. All that remains is to lift it vertically up and out of the hole.
Even if the sink removal is permanent, it may be a good idea to keep the water supply. One method for this is to move the supply lines into the wall and add a cover plate that can be used for future access. Adding plumbing to an existing building can be a challenge, so don't fully eliminate any plumbing you don't absolutely have to get rid of.