How to Install a Sink Faucet: A Step-by-Step Guide

Expert-backed tips to replace a kitchen or bathroom faucet like a pro

Co-authored by Dave Jones and Eric McClure

Last Updated: July 9, 2025 Fact Checked

Installing a sink faucet is one of the DIY jobs that anyone can do, so why pay a professional plumber? We'll walk you through exactly what you need to do to get the job done (and save some money while you're at it). For this article, we sat down with Dave Jones, a professional plumber and the Midwest Regional Vice President at Roto-Rooter Plumbing & Water Cleanup to get the low-down on how to swap a faucet out the right way.

How to Replace a Kitchen or Bathroom Faucet

Turn the water supply off and unscrew the supply lines. Remove the old faucet and clean the gunk off the sink. Then, install the faucet deck with caulk and assemble the faucet. Turn the water back on and test for leaks.

1

Gather the tools you’ll need.

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You may even have everything you already need. Special plumber's tools aren't required for this! You just need:
- A small bucket to catch residue water
- A towel to keep the bottom of the cabinet dry in case of a leak or spill.
- A replacement faucet.
- A basin wrench (optional, but very handy if your sink basin is deep and the faucet is hard to reach from under your sink).
- A wrench or pliers.
- Silicone caulk.
- Plumber’s tape.

2

Shut the water off.

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Use the shut-off valves under the sink to close the water lines. The shut-off valves are usually oval-shaped and sit on top (or at the end of) the hot and cold water pipes sticking out of the wall. David Jones says to gently turn each valve clockwise as far as it will go to shut the water off.^{[1]
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Expert Source

Dave Jones
Master Plumber, Roto-Rooter Plumbing & Water Cleanup

Expert Interview}
- If your home is especially old, check the condition of the supply lines for leaks or rust before opening them. You may want to replace these at the same time you replace the faucet.

3

Disconnect the supply lines.

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Use your wrench to unscrew the nut on top of each supply line. On top of each shutoff valve, there is a nut securing the supply line and preventing leaks.Use your wrench to loosen each nut and then twist it off by hand.^{[2]
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- Set the bucket under each line as you unlock it. Even with the water shut off, there’s still some leftover water in each line. A little water will pour out when you unlock each line—that’s completely normal.
- Does your replacement sink not come with supply lines? If your new sink doesn’t have supply lines pre-connected, and you plan on reusing the old supply lines (which is totally fine!), unscrew the nut where the line feeds into the faucet instead. There’s no point in undoing the lines at the wall if you’re just going to reinstall them later.

4

Remove the existing faucet.

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Unscrew the mounting nuts and lift the old faucet out. Jones explains that the mounting nuts are underneath the faucet, directly behind the sink. There may be 1-3 nuts depending on the design of the sink. Either unscrew the nuts by hand or use a basin wrench to unscrew them. You can also use channel locks or pliers to loosen each nut and untwist them by hand.^{[3]
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Expert Source

Dave Jones
Master Plumber, Roto-Rooter Plumbing & Water Cleanup

Expert Interview}
- Use a pillow to protect your back from the sharp point where the vanity sits on top of the ground if you’re uncomfortable.

5

Clean the sink where your faucet used to be.

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Scrape up any old gunk and wipe the sink down. Remove any old caulk or putty around the holes in the sink using your fingers or a putty knife. Then, use a damp washcloth and dish soap to scrub the holes where your old sink used to be. Clean each side of the sink thoroughly and wipe everything dry.^{[4]
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- Wear nitrile or rubber gloves if there’s a lot of gunk. It can be pretty gross if that faucet has been sitting there for more than a few years.

6

Prep the new faucet for installation.

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Modern faucets typically come pre-assembled, and you shouldn’t have to do much to set it up, but read the instructions anyway to see if there are any unique installation steps. If the faucet isn’t set up for installation, assemble the faucet. Jones says this process varies “model by model,” so just follow the instructions.^{[5]
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Expert Source

Dave Jones
Master Plumber, Roto-Rooter Plumbing & Water Cleanup

Expert Interview}

7

Position the deck plate with caulk.

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Use silicone caulk to adhere the deck to the top of the sink. The deck plate is the flat plate that sits on top of the holes on your sink. Add a bead of caulk around the interior of the deck plate, line it up with the holes on the sink, and press it into place. Wait at least 24 hours for the caulk to completely cure.^{[6]
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- Make sure the deck plate is oriented correctly! Some deck plates have a front and a back.
- You could theoretically install the faucet at the same time as the deck plate, but it’s best to install the deck plate first if you want to make things easy when it comes to lining the faucet up straight.

8

Install the faucet.

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Insert the faucet into the deck plate and tighten the nuts. Press the faucet down through the sink holes. Align the faucet, using the wall or the back of the sink to keep the faucet straight and lock it in place using the mounting nuts that connect to the fixture from underneath the sink.^{[7]
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- Jones says to hand-tighten the nuts that connect to the faucet assembly. You don’t need to the nuts to be crazy tight; they’re just holding the faucet in place and if you overtighten them, you might crack them.^{[8]
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  Expert Source
  
  Dave Jones
  Master Plumber, Roto-Rooter Plumbing & Water Cleanup
  
  Expert Interview}

9

Hook the supply lines back up.

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Reattach the supply lines with the basin wrench. Wrap plumber’s tape around the threading on the faucet connections to help seal the connections. Hook the hot supply line up to the hot water connection and the cold supply line to the cold connection. Tighten the hookup so using your basin wrench, channel locks, or pliers.^{[9]
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- If you’re hooking the supply lines up to your sink instead of the pipes on the wall, be careful and only move the nuts in half rotations to avoid bending or breaking anything.

10

Turn the water on and test your work.

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Turn the water on and see what happens. If you see any water dripping, turn off the valves and tighten the connection. If that doesn’t work, disassemble the hookup, add plumber’s tape, and re-tighten it. Repeat this process until everything is leak-free and working as intended.^{[10]
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Community Q&A

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Question

How do I install a faucet that doesn't have a cutoff valve?

Donagan

Top Answerer

You will have to shut off the main water supply to the building or the line out of the pressure tank if you have one. Then while you're installing the faucet, put in a shutoff valve.

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Question

How do I flush plumbing lines to clear any debris before starting installation of a faucet?

Community Answer

Attach the faucet hoses to the piping's stop/shut-off/isolation valves and turn the valves back on while holding the hoses in an empty bucket. Then, turn the valves back off once the water is running clear.

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Question

Should I caulk or silicone around a new faucet?

Community Answer

You can use a very small amount of silicone if you feel you need it. But faucets come with sealing gaskets or are made with flat bottoms to seal against the counter upon proper tightening. Only silicone if a leak is discovered after installation -- a leak is exceedingly rare.

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