Remove a Counter Top Sink
Turn off the water supply at the main supply valve. Test the faucet to confirm it is turned off.
Put a bucket under the trap. Loosen the nuts surrounding the trap and remove it allowing the excess water to empty into the bucket.
Take out the water supply to the faucet. Confirm that all plumbing is disconnected from the sink. Place a rag in the main drain to block any gases.
Look for clips under the bathroom sink. Loosen them completely. If you are unable to take them out easily, then break them off.
Cut the seal with a utility knife that is between the counter and the rim of the sink. Or, if the sink and countertop are one piece, cut the seal along the vanity. To remove it, use a small pry bar.
Raise the whole thing straight up. It should release it from the counter.
Remove a Wall-Mounted Sink
Get someone to help you. The sink is probably heavier than you think. Once you take out the plumbing and brackets or bolts, the sink will not be supported.
Turn off the water supply for the bathroom at the main supply valve. Test the faucet to confirm it is turned off.
Put a bucket under the trap. Loosen and remove any nuts that surround the trap. Allow the excess water to empty into the bucket.
Remove the water supply that connects to the faucet. Confirm that all plumbing is disconnected. Place a rag in the main drain to block any gases.
Check to see if the sink is mounted with a bracket. This bracket will make it easy to lift out once the plumbing is disconnected. Take out the bracket and have your helper lift it out.
See if it is bolted to the wall. Have someone hold the sink while you remove the bolts to release it.