How to Replace a Kitchen Faucet: Compatibility, Installation, and Leak Testing

Replacing a kitchen faucet is manageable when the new model matches the sink’s hole layout and the supply connections are in good condition. The work follows four main stages: confirm compatibility, remove the old faucet, install and align the new one, and test every connection before restoring full water pressure.

Stop and call a plumber if a shutoff valve will not close, a mounting nut or supply fitting is seized, the sink or countertop is cracked, or the existing plumbing must be modified.

Before You Buy: Confirm the Sink and Faucet Are Compatible

Count the sink holes

Most kitchen sinks have one, three, or four holes:

• One hole supports a single-hole faucet.
• Three holes may support a faucet with separate handles, a side sprayer, or a deck plate.
• Four holes often include a side sprayer, soap dispenser, or filtered-water tap.

Measure the hole spacing

Measure center-to-center between the outer holes. Do not estimate from the sink width. The new faucet, deck plate, or integrated side sprayer must match the actual drilling pattern.

Check deck clearance and spout reach

Confirm that the faucet base fits flat on the sink deck and that the spout reaches far enough into the sink without hitting the backsplash. Also check handle clearance and whether the faucet can swivel without contacting nearby objects.

Confirm under-sink space

Measure the available depth for mounting hardware, hoses, the pull-down weight, and the sprayer hose. A large faucet may fit the sink but still interfere with the cabinet, plumbing, or a water-filtration system.

Inspect the existing valves and supply lines

Close and reopen the hot and cold shutoff valves before starting. Replace a valve that does not shut off completely. Inspect the supply lines for corrosion, stiffness, cracks, or damaged fittings.

Tools and Materials

Prepare the following before working under the sink:

• Adjustable wrench
• Basin wrench for mounting nuts
• Phillips and flat-head screwdrivers
• Allen keys for handle set screws
• Bucket and absorbent towels
• Flashlight or headlamp
• Replacement supply lines if needed
• Compatible sealant or plumber’s putty
• Manufacturer’s installation instructions

Putty and silicone are not interchangeable in every application. Plumber’s putty is commonly used on stainless steel and porcelain, while 100% silicone is generally required on natural stone such as granite or marble because putty oils can stain porous surfaces. Always follow the sink and faucet manufacturer’s instructions.

Safety and Preparation

1. Clear the cabinet and protect the cabinet floor.
2. Close the hot and cold shutoff valves.
3. Open the old faucet to relieve pressure.
4. Disconnect the sprayer and let residual water drain into a bucket.
5. Take photos before removing parts.
6. Keep small screws, clips, and mounting parts in a tray.

If the shutoff valves do not stop the water, turn off the main supply before continuing.

Step 1: Disconnect the Old Supply Lines

1. Place a towel and bucket below the connections.
2. Loosen the hot and cold supply nuts with an adjustable wrench.
3. Hold the fitting steady so the supply pipe does not twist.
4. Catch residual water and separate the lines from the faucet.
5. Label the hot and cold lines if they are not already marked.

Do not force a corroded nut. Penetrating oil may help after the water is off, but allow it time to work and protect surrounding surfaces.

Step 2: Remove the Old Faucet

1. Disconnect the sprayer hose and pull-down hose if present.
2. Remove the counterweight from the hose.
3. Use a basin wrench to loosen the mounting nuts underneath.
4. Support the faucet from above before removing the final nut.
5. Lift the faucet and old gasket away from the sink.
6. Clean old putty, silicone, mineral deposits, and debris from the sink deck.

If the mounting nut is seized, stop before damaging the sink or countertop.

Step 3: Prepare the New Faucet

1. Read the installation manual and identify every supplied part.
2. Confirm the hot and cold inlet orientation.
3. Install the gasket or sealant according to the manufacturer.
4. Route flexible hoses so they will not twist or rub.
5. If a deck plate is used, confirm that it covers the unused holes.
6. Test-fit the faucet before applying permanent sealant if clearance is uncertain.

Step 4: Install and Align the Faucet

1. Feed the hoses and threaded mounting parts through the sink holes from above.
2. Position the faucet so the handle and spout face the intended direction.
3. Install the washer and mounting hardware from below.
4. Start the nuts by hand before using a wrench.
5. Have someone hold the faucet straight from above while tightening from below.
6. Tighten until the faucet is secure, but do not crush the gasket or crack the sink.

After tightening, check that the base sits flat and the spout can move through its full range.

Step 5: Connect the Supply Lines

1. Match the hot line to the hot inlet and the cold line to the cold inlet.
2. Start each threaded connection by hand.
3. Tighten gently with a wrench.
4. Avoid overtightening, which can damage rubber seals and deform washers.
5. Check that the lines do not kink or press against sharp cabinet edges.

Follow the manufacturer’s guidance on thread sealant or PTFE tape. Not every faucet connection requires tape.

Step 6: Install the Pull-Down or Pull-Out Hose

1. Connect the hose according to the manufacturer’s instructions.
2. Push quick-connect fittings until they click or lock.
3. Verify that the retaining clip or locking feature is fully engaged.
4. Attach the counterweight at the starting position shown in the manual.
5. Pull the spray head through its full range and check for hose twisting.
6. Move stored items out of the hose path inside the cabinet.

The counterweight should allow the spray head to retract smoothly. If the hose hangs low or catches, adjust the weight only after checking the manual.

Step 7: Perform the Leak Test

1. Leave the faucet handle open.
2. Open the shutoff valves slowly.
3. Allow trapped air to escape.
4. Close the faucet and inspect the supply connections.
5. Run hot water, then cold water.
6. Test the sprayer and swivel the spout through its full range.
7. Dry every connection and watch for new moisture.
8. Check again under the cabinet after several minutes of use.

If a connection drips, turn off the water before tightening it. Tighten only slightly and recheck. If the leak continues, inspect the washer, ferrule, and fitting alignment.

Troubleshooting After Installation

When to Stop and Call a Plumber

Call a licensed plumber when:

• A shutoff valve will not close fully.
• A mounting nut or supply fitting is seized or stripped.
• The sink or countertop is cracked.
• The existing pipe must be moved or modified.
• The faucet requires a new hole in stone or a structural surface.
• A leak continues after the correct connection procedure.
• The cabinet contains damaged wiring, mold, or long-term water damage.

Frequently Asked Questions

Can I replace a three-hole faucet with a single-hole faucet?

Often yes, if the manufacturer provides a compatible deck plate that covers the unused holes and fits the sink contour.

How long does a kitchen faucet replacement take?

A straightforward replacement may take one to three hours. More time is needed for corroded fittings, limited cabinet access, or supply-line replacement.

Should I use plumber’s putty or silicone?

Use the material specified for the faucet and sink. Silicone is generally required on natural stone because plumber’s putty can stain porous surfaces.

Do I need to replace the supply lines?

Replace a line that is cracked, stiff, corroded, damaged at the fitting, or too short for the new faucet.

What if the new faucet leaks after installation?

Turn off the water, dry the connection, and inspect the washer, ferrule, and fitting alignment. Tighten slightly and retest. Replace a damaged seal or line rather than increasing force.

Final Takeaway

A successful kitchen faucet replacement begins with compatibility checks, not the purchase. Count the holes, measure the spread and clearance, inspect the shutoff valves, remove the old faucet carefully, and follow the manufacturer’s sealing and hose instructions.

Test the faucet through hot, cold, spray, swivel, and retraction cycles. Inspect both the faucet base and the cabinet below before considering the installation complete.