Replacing a kitchen faucet is one of the most satisfying home upgrades you can do in an afternoon. A new faucet transforms the look of the kitchen sink area and often improves functionality with better spray heads, higher arcs, and smoother operation. The plumbing connections are simpler than most people expect.

How to Install a Kitchen Faucet

Choosing a New Faucet

Before you shop, check two things:

Number of mounting holes. Look under the sink or behind the existing faucet to count the holes in the sink or countertop. Common configurations are one hole, three holes, or four holes. Your new faucet must match, or you need a deck plate (a cover plate) to span multiple holes with a single-hole faucet.

Supply line connections. Most modern faucets use standard 3/8-inch compression fittings, which match the supply lines already under your sink. Verify before buying.

Tools and Materials

• New faucet (with supply lines if not included)
• Basin wrench (essential for reaching nuts under the sink)
• Adjustable wrench
• Plumber’s tape (Teflon tape)
• Bucket and towels
• Flashlight or headlamp
• Plumber’s putty or silicone (for sealing the base)

Removing the Old Faucet

Turn Off the Water

Open the cabinet under the sink and locate the hot and cold shutoff valves. Turn them clockwise to close. Open the faucet to release pressure and confirm the water is off.

If the shutoff valves do not fully stop the flow (a common problem with old gate valves), turn off the water at the main shutoff.

Disconnect the Supply Lines

Place a bucket under the connections to catch residual water. Use an adjustable wrench to disconnect the supply lines from the shutoff valves or from the faucet tailpieces.

Remove the Faucet

Reach under the sink with a basin wrench and unscrew the mounting nuts that hold the faucet to the sink. A basin wrench has a pivoting jaw on a long handle — it is specifically designed for the awkward, tight space under a sink.

Once the nuts are off, lift the old faucet out from above. Clean any old putty or silicone residue from the sink surface.

Installing the New Faucet

Prepare the Base Seal

Apply a bead of plumber’s putty or silicone sealant around the base of the new faucet’s deck plate or around the base of the faucet body. This prevents water from seeping under the faucet and into the countertop or cabinet.

Some faucets include a rubber or foam gasket that eliminates the need for putty. Follow the manufacturer’s instructions.

Set the Faucet

Feed the supply lines and any sprayer hose down through the mounting hole(s). Set the faucet base on the sink, pressing it into the putty or gasket. Check alignment from the front before tightening.

Secure from Below

Reach under the sink and hand-thread the mounting nuts onto the faucet tailpieces. Tighten with the basin wrench. Do not overtighten — snug plus a quarter turn is enough. Plastic mounting nuts crack under excessive force.

For single-hole faucets with a mounting bracket, tighten the bracket screws evenly to pull the faucet down flat against the sink.

Connect the Supply Lines

Wrap the threaded fittings on the shutoff valves with Teflon tape (two to three wraps clockwise). Connect the hot supply line to the hot valve (usually the left) and the cold to the cold (right).

If the faucet came with braided stainless steel supply lines pre-attached, you only need to connect them to the shutoff valves. These pre-attached lines are a major time saver.

Hand-tighten the connections, then snug with an adjustable wrench — a quarter turn past hand-tight is sufficient. Over-tightening deforms the ferrule and causes leaks.

Connect the Sprayer (If Applicable)

Pull-down and pull-out sprayer hoses connect under the sink with a quick-connect fitting. Push the hose end into the fitting until it clicks. Tug to confirm it is locked.

For side-sprayer models, feed the sprayer hose through its separate mounting hole and connect it to the diverter on the faucet body with the provided coupling.

Testing

Turn the shutoff valves back on slowly. Let air bleed out of the faucet by running both hot and cold for 30 seconds. Check every connection under the sink for drips — place a dry paper towel under each fitting and check it after five minutes.

Test the sprayer function, the hot/cold mixing, and the handle operation. Wipe away any excess putty that squeezed out around the base.

Common Issues

Faucet base is not level. The mounting hole may be slightly off-center, or the countertop surface is uneven. Adjust the position of the deck plate or use shims before tightening.

Low water pressure after installation. Remove the aerator from the faucet spout and check for debris. New faucets often have small pieces of debris from manufacturing that clog the aerator screen.

Leak at the supply line. Loosen the fitting, add another wrap of Teflon tape, and retighten. If it still leaks, the ferrule or supply line may be damaged — replace the supply line.

A new kitchen faucet makes the most-used fixture in your home look and work better. The whole job typically takes 30 to 60 minutes, most of which is spent under the sink with the basin wrench.