How to Install a New Kitchen Faucet

Installing a new kitchen faucet is one of those projects that looks harder than it actually is. The work happens in a tight space under the sink where you can't see much, which creates the illusion of complexity, but the steps themselves are straightforward: disconnect the old lines, unbolt the old faucet, drop in the new one, and reconnect everything. What separates a smooth installation from a frustrating one is preparation—knowing where your water shutoff is, having the right tools within arm's reach, and understanding that some faucets come with compression fittings while others use quick-connect adapters. A well-installed faucet runs smoothly for years without drips or leaks. A rushed one becomes a source of regret every time you look under the sink.

1. Shut Off Water First. Locate the shutoff valves beneath your sink—one for hot water, one for cold. Turn both clockwise until they stop. Open the faucet above to confirm the water is off. If you can't find shutoff valves under the sink or they don't work, find the main shutoff valve in your basement or utility closet and turn that off instead.
2. Free the Supply Lines. Place a bucket under the connection points. Use an adjustable wrench to loosen the compression nuts where the supply lines connect to the shutoff valves. Turn by hand once they're loose enough. If water drips out, let it drain into the bucket. Disconnect both hot and cold lines completely.
3. Unbolt the Old Base. Reach up inside the cabinet from below and locate the mounting nuts that hold the faucet to the sink deck. Most faucets have two or three nuts. Use a wrench or socket to loosen and remove them. The faucet should drop down into the sink from above. If it's stuck, run a utility knife around the base to break the caulk seal, then wiggle gently.
4. Prepare the Sink Deck. Pull out the old faucet and set it aside. Use a putty knife or scraper to remove old caulk and any mineral buildup from the sink deck where the faucet sat. Wipe the area clean with a damp cloth and dry it thoroughly. A clean surface ensures your new faucet will seal properly.
5. Assemble Before Installing. Before the faucet goes into the sink, assemble any components according to the manufacturer's instructions. This typically means installing the aerator, securing the spray head hose if applicable, and attaching the supply line adapters or tubes. Work on a towel so you don't lose small parts. Tighten everything hand-tight, then add a quarter turn with a wrench.
6. Lower the New Faucet. Carefully lower the assembled faucet down through the sink deck holes from above. Feed the supply tubes down into the cabinet. Center the faucet so it's straight and aligned with the sink. The base should sit flat on the deck with no rocking. You may need to adjust or shim the base so it's level.
7. Bolt Down the Base. From underneath the sink, hand-thread the mounting nuts onto the faucet bolts. Once they're snug by hand, use a wrench or socket to tighten them in a cross pattern—tighten one side a quarter turn, then the opposite side a quarter turn—as if you're tightening a bolt circle. Work evenly so the faucet doesn't tilt. Stop when you feel resistance; don't over-tighten.
8. Reconnect the Water Lines. Take the hot water supply line from the faucet and thread the compression nut onto the hot water shutoff valve. Tighten by hand until snug, then use a wrench for an additional half turn. Repeat with the cold water line and the cold shutoff valve. Listen and feel for leaks as you gradually turn the shutoff valves back on. Open them slowly—don't suddenly blast water through new connections.
9. Test for Leaks Now. Open the faucet fully and run both hot and cold water for one minute. Switch between hot and cold several times. If your faucet has a spray head, activate it and check for even spray. Watch under the sink for any drips or spray coming from the connections. Let the water run for a full minute before calling it good.
10. Seal the Base Joint. Once you're confident there are no leaks, apply a bead of silicone caulk around the base of the faucet where it meets the sink deck. Use a wet finger to smooth it into a clean line. This prevents water from running down into the cabinet. Let the caulk cure according to the manufacturer's instructions—typically 24 hours—before using the sink heavily.
11. Thread In the Aerator. If your faucet came with a separate aerator that isn't pre-installed, hand-thread it into the spout opening. Tighten it with a wrench, but gently—you're just sealing it, not cranking it. An over-tightened aerator is difficult to remove later.