How to Caulk a Bathroom Sink

Co-authored by Ryaan Tuttle

Last Updated: July 29, 2024

Drop-in sinks are made to hang from the top of a counter by their rims. While these rims appear to sit flush to the counter, there is actually a small gap between the rim and counter where water and debris can collect. Caulk fills this gap to make your counter and sink watertight, while helping to eliminate any movement of the rim of the sink. To help prevent leaks or damage to your counter, seal and fill this gap with waterproof caulk whenever the old caulk begins to crack, discolor or peel.

Steps

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Make sure the area is clean and dry and has no dust or debris to get in the way of the caulk.
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Remove any old caulk from the edge of the sink with a sharp utility knife. Caulk is a soft material that cuts easily and stretches when pulled.^{[1]
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- You can also remove caulk with a special tool. It is typically plastic and has a little pointy thing on it that helps you pull the caulk out. It is usually available in a painting section of a home improvement store.
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Pull the caulk free from the sink and counter.^{[2]
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Cut just enough of the tip off to allow the caulk to fill the gap next to the rim; cutting away too much of the tip will mean too much caulk on your counter.
Squeeze the trigger lightly to prime the tube.
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Wet your index finger with water and gently smooth the caulk against the side of the sink's rim and the counter top to completely seal the gap.
When you are happy with the results, insert a small screw into the tip to seal the tube of caulk, so you can use it again in your next project.

Community Q&A

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Question

Do I have to caulk a regular bathroom sink all around, or just the front, top and sides?

Community Answer

Just the front, top and sides need to be sealed, no need to seal underneath.

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Can I put two coats of sealer on?

Community Answer

Absolutely. Put on as many coats as it takes to get everything smooth and flushing.

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Tips

If excess caulk gets on the counter or sink, clean it up with a wet paper towel before it solidifies.

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Get a caulk in the same color as your bathroom sink for the most unobtrusive appearance.

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