You can replace a Delta kitchen faucet yourself in about an hour with basic tools

Replacing a Delta kitchen faucet is a straightforward job that does not require a plumber. You will need an adjustable wrench, a basin wrench (a specialized tool that costs $10 to $20 and makes the job much faster), a bucket or towel to catch water, and possibly a screwdriver. The entire process takes 45 minutes to an hour if the old faucet comes out cleanly. The hardest part is usually reaching the nuts under the sink, not the actual disconnection or installation.

Before you start, turn off the water supply valves under the sink by turning them clockwise. If you do not see valves there, you will need to shut off the main water supply to your house. Open the faucet to release any remaining pressure in the lines.

Key Takeaways

  • Turn off the water supply valves under the sink before disconnecting anything, or shut off the main water supply if those valves are missing.
  • A basin wrench makes removing the old faucet much easier by letting you reach the mounting nuts from below without removing the entire sink.
  • Delta faucets typically connect with two or three mounting nuts and two supply lines that you disconnect by hand or with a wrench.
  • The new faucet installs in reverse order: position it, hand-tighten the mounting nuts, connect the supply lines, and turn the water back on to test for leaks.
  • If the old faucet is stuck or corroded, explore penetrating oil and waiting 15 to 20 minutes can make removal much easier.

Disconnect the old faucet from the water supply lines

Look under the sink at the two flexible hoses or rigid copper tubes connected to the faucet. These are the hot and cold water supply lines. Place a bucket or towel underneath to catch any water still in the lines. Use an adjustable wrench to loosen the nut where each supply line connects to the faucet. Turn counterclockwise until the connection is loose enough to unscrew by hand, then pull the lines away from the faucet.

If the supply lines are old and corroded, the nuts may be very tight. Spray penetrating oil around the nut, wait 15 to 20 minutes, and try again. Do not force it hard enough to strip the nut or damage the fitting.

Remove the mounting nuts holding the faucet in place

The faucet is held to the sink from below by two or three mounting nuts. These are the hardest part to reach because they sit in a tight space under the sink. A basin wrench is designed exactly for this job: it has a long handle and a small head that fits into tight spaces. Slide the basin wrench up to the nut, position the head around it, and turn counterclockwise to loosen.

If you do not have a basin wrench, an adjustable wrench or crescent wrench will work, but you will have less leverage and may need to remove items stored under the sink to get your hand in position. Loosen all the mounting nuts until they are hand-tight, then unscrew them the rest of the way by hand. Keep them in a safe place in case you need them later.

Once the nuts are off, lift the old faucet straight up and out of the sink. If it does not budge, there may be caulk or mineral buildup around the base. Run a utility knife around the edge to break the seal, then try again.

Clean the sink surface before installing the new faucet

With the old faucet out, you will see the holes in the sink where it was mounted. Wipe away any old caulk, mineral deposits, or debris with a damp cloth or sponge. If there is heavy buildup, a plastic scraper or old credit card works well without scratching the sink. Let the surface dry completely before you install the new faucet.

Check the new Delta faucet to see if it comes with a rubber or foam gasket at the base. If it does, leave it in place. If not, you may want to explore a thin bead of plumber's caulk around the base of the faucet after installation to prevent water from running underneath.

Position the new faucet and find the mounting nuts

Lower the new Delta faucet into the holes in the sink. Make sure the spout points in the direction you want it to face and that the faucet sits flat against the sink. Slide the mounting nuts onto the threaded posts from underneath. Hand-tighten them first so the faucet stays in place but you can still adjust its position if needed.

Once the faucet is positioned correctly, use the basin wrench to tighten each mounting nut clockwise. Tighten them evenly so the faucet sits flat and does not rock. You do not need to crank them down hard — snug is enough. Over-tightening can crack the sink or strip the threads.

Connect the new supply lines and test for leaks

Take the hot and cold water supply lines from the new faucet and connect them to the hot and cold valves under the sink. Hand-tighten the connection nuts first, then use an adjustable wrench to tighten them another quarter turn. They should be snug but not so tight that you cannot loosen them later if you need to.

Turn the water supply valves back on by turning them counterclockwise. Open the faucet and let water run for 30 seconds to flush out any debris from the lines. Check under the sink for drips at the supply line connections and at the base of the faucet. If you see water dripping, tighten the connection nut a little more. If the leak continues, turn off the water, disconnect the line, and check that the ferrule (the small metal or plastic ring) is seated properly before reconnecting.

Adjust the faucet handle and finish the installation

Most Delta kitchen faucets come with a handle that needs to be positioned and secured. Slide the handle onto the stem, position it so it points down when the water is off, and tighten the set screw (usually a small hex screw) with an Allen wrench or screwdriver. Check your faucet's manual for the exact location and size of the set screw.

If your new faucet came with a decorative collar or escutcheon (the ring that covers the hole in the sink), slide it down over the faucet stem and tighten it by hand. Some models have a set screw for this as well. Test the handle by turning it on and off a few times to make sure it moves smoothly and the water shuts off completely.

Frequently Asked Questions

What if I cannot turn off the water valves under the sink?

If the valves are stuck or missing, you will need to shut off the main water supply to your house. This is usually a valve near the water meter or where the main line enters the house. Turn it clockwise until it stops. If you cannot find it or it will not turn, call a plumber before you start the faucet replacement.

Can I reuse the old supply lines with the new faucet?

You can reuse them if they are in good condition and the connection fittings match the new faucet. However, if the lines are more than 10 years old, kinked, or corroded, it is worth replacing them at the same time. New braided supply lines cost $10 to $20 and are easier to work with than old rigid copper.

Why is water leaking from under the sink after I installed the new faucet?

Check the connection nuts on the supply lines first — they may need another quarter turn. If the leak is coming from the base of the faucet where it meets the sink, the gasket may not be seated properly. Turn off the water, remove the mounting nuts, lift the faucet out, and check that the rubber gasket is in place and not twisted or torn.

Do I need plumber's caulk around the base of the faucet?

If your faucet came with a rubber gasket, caulk is optional. If it did not, a thin bead of silicone caulk around the base prevents water from running underneath the faucet and into the cabinet. Use caulk rated for kitchens and let it cure for 24 hours before using the faucet heavily.

What should I do with the old faucet?

If it still works, you can donate it or sell it online. If it is broken or corroded beyond use, most recycling centers accept metal faucets. Some plumbing supply stores also take old faucets for recycling. Do not throw it in the trash if your area has a metal recycling program.