Some time ago, here on Ruvati.com, we published a guide on how to replace your kitchen faucet.
In this guide, we want to tell you how to install one from scratch. The steps are a bit different, as installation presumes that there is nothing already installed and you have to perform all of the steps from scratch.
We’ll start off with what tools you need, and then we will talk about the steps in detail, as well as some common mistakes and pitfalls to avoid.

• New kitchen faucet
• Plumber’s tape (Teflon tape)
• Plumber’s putty or silicone caulk (check your faucet instructions because some come with gaskets)
• New supply lines (don’t reuse old ones if they’re crusty or kinked)

• A pillow or foam pad to lie on (if you were born before 2000)
• Paper towels (lots of them)
• Zip-top bags for screws and small parts
• Marker or masking tape to label connections
• WD-40 or penetrating oil (for stuck nuts)
• Extra rags stuffed around pipes
• A phone or tablet to reference instructions while you’re under the sink
• Someone to hand you tools (optional, but makes life easier)
• Aspirin…because you might bump your head and get a headache

Seriously, buy the basin wrench. A regular wrench won’t reach the mounting nuts.

Clear out everything from under the sink. You need room to move, and you’re going to be spending time down there. Lay down a pillow or foam pad on the cabinet floor. Your back and neck will be pressed against hard surfaces, and comfort matters when you’re working in awkward positions.

Set up your flashlight or headlamp before you get into position. You don’t want to be fumbling in the dark trying to find it. Keep all your tools within arm’s reach. A bucket, rags, and your wrenches should be right next to you.

Pro tip: If you have a headlamp, use it. Holding a flashlight in your mouth while trying to tighten nuts is miserable.

Assuming that you’re installing a faucet from scratch, the water supply will be closed off, and the valves will be properly shut. However, since you’re getting all close up in the area and you’ll be tinkering with the pipes, just take a minute and make sure that the supply is sealed shut so that nothing starts leaking once the installation is underway.

Before you start with the installation, make sure that the sink has the same (or more) number of holes that you need for your faucet. If there are fewer, then you will either need to get a different faucet or make a new hole.

Look at your sink from above. Count the holes. Most kitchen sinks have either one hole, three holes, or four holes. Measure the distance between the outer holes if you have multiple holes. This is usually 8 inches, but confirm it.

Lay out all the parts from the box on your counter and compare them to the parts list in the instruction manual. Make sure everything is included before you start.

You’re looking for the following parts:

• Faucet body
• Mounting hardware, nuts, washers, screws
• Supply lines
• Deck plate, if applicable
• Gaskets or seals

Take a few minutes to read the manufacturer’s instructions now. Every faucet is a little different, and some include specific assembly steps that are much easier to understand before you’re under the sink.

Some faucets come partially assembled, while others require you to put pieces together first. If your faucet has a separate spout, handle, or sprayer component, attach those now while you’re standing at the counter where you can see what you’re doing.

• Connect any hoses that need to be attached to the faucet body
• Tighten connections by hand first, then use a wrench if needed
• Don’t overtighten plastic parts—they crack easily
• Attach the mounting hardware loosely so you can adjust it later

Check if your faucet came with a rubber gasket on the bottom. If it did, leave it in place. The gasket creates a watertight seal between the faucet and the sink, and you don’t need to add anything else.

If you’re using a deck plate to cover extra holes, install it before the faucet. Thread the faucet’s supply lines through the center hole of the deck plate first. Lower the deck plate onto the sink so it covers all the holes. Make sure it’s centered and sitting flat against the sink surface.

Some deck plates come with their own gasket or require a bead of silicone caulk underneath. Check your instructions.

From above the sink, feed the supply lines (the hoses hanging from the faucet) down through the sink hole. If you have a three-hole setup, the supply lines and faucet body go through the center hole, and the handles or side sprayer go through the outer holes.

Crawl under the sink with your basin wrench, mounting hardware, and flashlight.

Look up at the underside of the sink. You’ll see the threaded tailpieces (metal tubes) sticking down through the holes. These are what you’ll use to secure the faucet.

Take your roll of plumber’s tape (Teflon tape) and find the threads on the shutoff valves. Starting at the base of the threads, wrap the tape clockwise around the valve 3 to 4 times. Overlap each wrap slightly and press the tape down so it sticks to the threads.

This tape prevents leaks at the connection points.

Grab the supply line marked for hot water (usually has a red tag or indicator). Thread the nut onto the hot water shutoff valve by hand. Turn it clockwise and tighten as much as you can with your fingers.

Use your adjustable wrench to snug it up. Go about a quarter turn past hand-tight. You want it secure, but you don’t want to crack the fitting.

Repeat the process for the cold water supply line on the cold water valve (usually marked with blue). Make sure you’re not mixing them up—hot goes to hot, cold goes to cold.

Now connect the other ends of the supply lines to the faucet tailpieces. These are the threaded tubes sticking down from the faucet body.

If your faucet has a pull-down or pull-out sprayer, the hose is already attached to the faucet body. But if you have a separate side sprayer, you need to connect it now.

Stay under the sink for this part. You want to watch for leaks as the water pressure builds.

Turn one shutoff valve counterclockwise—slowly. Open it just a little bit at first. Watch the connection where the supply line meets the valve. If you see water dripping, turn the valve back off and tighten that connection slightly. If it’s dry, keep opening the valve until it’s fully open.

Repeat for the second shutoff valve. Keep your eyes on all the connections. Water should flow through the lines to the faucet, but nothing should be dripping or spraying.

Stay under the sink. Have someone turn on the faucet above. If you’re alone, reach up and turn it on yourself, then quickly get back under to watch for leaks.

Go back above the sink. Turn the faucet handle (or handles) and make sure they move smoothly. Check that hot water comes out when you turn the hot handle and cold water comes out when you turn the cold handle. It sounds obvious, but if you mixed up the connections, now’s the time to find out.

If your faucet has a pull-down or pull-out sprayer, test it. Pull the spout out, switch between spray modes, and let it retract. Make sure the hose moves freely, and the weight is doing its job.

If you have a separate side sprayer, squeeze the trigger and make sure water comes out with good pressure. Check that it retracts smoothly when you let go.

Look at the base of the faucet where it meets the sink. If you used plumber’s putty, some of it probably squeezed out. That’s normal. Use your finger or a putty knife to scrape away the excess. Wipe the area clean with a damp rag.

Check for any water pooling around the base. If the area is wet, the seal might not be tight enough. You may need to go back under and tighten the mounting nuts a bit more.

Wipe down the entire faucet to remove fingerprints and smudges. Clean the sink area while you’re at it.

Run the faucet for a few minutes. Let both hot and cold water flow. While it’s running, go back under the sink and check all the connections one more time. Sometimes a slow drip doesn’t show up until water has been flowing for a while.

If everything is dry, you’re done. Put your tools away and replace whatever you removed from under the sink.

Check under the sink again in an hour. Then check it again the next morning. Slow leaks sometimes take time to show up, especially if a connection is just barely loose. Better to catch it early than to discover a puddle three days later.

Installing a kitchen faucet from scratch is one of those projects that looks harder than it actually is. Once you have the right tools and you understand the sequence of steps, it’s not that hard. Most installations take an hour or two, and that includes the time spent crawling under the sink and double-checking connections.

The key is preparation. Know your sink’s hole configuration before you buy a faucet. Have all your tools ready before you start. Test your shutoff valves to make sure they actually work. If you do those things, the installation itself is straightforward: thread the faucet through the holes, tighten the mounting nuts, connect the supply lines, and check for leaks.

Don’t skip the final checks. Run water through the faucet for a few minutes while you watch the connections. Check again in an hour. Check again the next day. A small drip caught early is easy to fix. A leak that goes unnoticed for a week can damage your cabinets and flooring. Take the time to make sure everything is dry and secure before you call the job done.