What you need before you start

Replacing a kitchen faucet is a task most homeowners can do in an afternoon with basic tools. You will need an adjustable wrench, a Phillips head screwdriver, a flathead screwdriver, and a bucket or towel to catch water. Some faucets come with their own wrench; check the box before you buy tools. You should also have plumber's putty or caulk on hand, depending on what your new faucet requires.

Before you buy a replacement faucet, measure the distance between the holes in your sink or countertop. Most kitchen sinks have either a single hole (for a single-handle faucet) or three holes (for a two-handle faucet with a separate sprayer). Some newer sinks have two holes. The faucet you buy must match your sink's configuration, or you will need to drill new holes or fill old ones.

Turn off the water supply before you touch anything under the sink. Look for two shut-off valves — one for hot water, one for cold — usually located on the pipes beneath the sink. Turn both clockwise until they stop. If you cannot find shut-off valves under your sink, you may need to shut off the main water supply to your house. Test that the water is off by turning on the faucet; if water still comes out, the shut-off did not work.

Key Takeaways

  • Turn off both hot and cold water shut-off valves under the sink before you disconnect anything, or you will have water pouring out when you remove the old faucet.
  • The hardest part is usually loosening the nuts that hold the old faucet in place; they are often corroded and tight, and you may need to work from underneath the sink with limited space.
  • New faucets come with mounting hardware and instructions specific to that model; follow those instructions rather than assuming all faucets install the same way.
  • After you connect the new faucet, turn the shut-off valves back on slowly and check for leaks at every connection before you consider the job done.

Removing the old faucet

Get under the sink with your bucket or towel. You will see the water supply lines (usually flexible hoses) connected to the shut-off valves, and you will see the faucet body mounted from above. Use your adjustable wrench to loosen the nuts that connect the supply lines to the faucet. Turn counterclockwise and work slowly — these nuts are often stuck. Once the supply lines are loose, pull them away and let any remaining water drain into your bucket.

Next, look at how the faucet is mounted to the sink. Most faucets are held down by nuts on the underside of the sink, or by a mounting bracket. Use your wrench to loosen these nuts, turning counterclockwise. You may need to hold the faucet steady from above while you work underneath. Once the nuts are loose enough, go back to the top of the sink and pull the old faucet straight up and out. It should come free once all the nuts are removed.

Clean the sink surface where the old faucet was mounted. Scrape off old putty or caulk with a flathead screwdriver. Wipe the area dry with a cloth. This step matters because the new faucet will not seal properly if debris is in the way.

Installing the new faucet

Open the box and lay out all the parts. Most new faucets come with a rubber gasket or mounting ring, supply lines (sometimes), and a set of mounting nuts. Read the instructions that came with your faucet — different models install differently, and the instructions will tell you the exact order of steps and which parts go where.

If your faucet requires plumber's putty, roll a thin rope of it and place it around the base of the faucet where it will sit on the sink. If it requires caulk instead, you will apply that after the faucet is mounted. Lower the new faucet into the hole (or holes) from the top of the sink, making sure it sits straight and level.

From underneath, slide the rubber gasket and mounting ring onto the faucet body if your model uses them. Hand-tighten the mounting nuts, then use your wrench to tighten them fully. Do not over-tighten; you want them snug, not cranked down with all your strength. Tighten in a cross pattern if there are multiple nuts, the same way you would tighten a car wheel, so the faucet sits evenly.

Connecting the water supply lines

Most new faucets come with flexible supply lines already attached. If yours does not, you will need to buy supply lines that match your faucet's connection size — usually 1/2 inch. Connect the hot water line to the hot water port on the faucet and the cold water line to the cold water port. Hand-tighten these connections first, then use your wrench to snug them up. Again, snug is the goal, not maximum force.

Connect the other end of each supply line to the shut-off valve under the sink. The nut should tighten by hand most of the way; use your wrench for the final quarter-turn. If the line does not reach the shut-off valve, you bought the wrong length — measure and get a longer one before you proceed.

Testing for leaks

Turn the shut-off valves back on slowly, opening them counterclockwise. Listen and watch for water spraying or dripping. Turn on the faucet at the sink and let water run for 30 seconds. Check every connection you made — under the sink at the supply lines, at the shut-off valves, and at the faucet body itself. Wipe each connection with a dry cloth and watch for new moisture.

If you see a drip, turn the shut-off valves back off and tighten the leaking connection a quarter-turn with your wrench. Turn the water back on and check again. Most small leaks stop after one more tightening. If a connection keeps leaking after you have tightened it twice, turn off the water, disconnect it, wrap the male threads with plumber's tape (three wraps, clockwise), and reconnect it.

Once you have confirmed there are no leaks, run hot and cold water through the faucet and check the spray function if your faucet has one. The job is complete when water flows smoothly and nothing drips.

Sealing the base if needed

If your faucet came with caulk instead of putty, or if you see gaps between the faucet base and the sink, apply a bead of caulk around the base now. Use a caulk gun and silicone caulk rated for kitchens. Run a smooth bead all the way around, then use a wet finger or caulk tool to smooth it. Let it cure for 24 hours before you use the sink heavily.

If you used plumber's putty, you can smooth it now or leave it as is. Putty does not cure the way caulk does; it simply stays in place. Wipe away any excess with a damp cloth.

Frequently Asked Questions

What if the old faucet nuts are stuck and will not turn?

Spray the stuck nut with penetrating oil (like WD-40) and wait 15 minutes. Try again with your wrench. If it still will not budge, spray again and wait an hour. You can also try tapping the nut gently with a hammer to break the corrosion. Do not force it hard enough to strip the threads or break the fitting.

Can I install a new faucet if my sink has the wrong number of holes?

If your new faucet needs fewer holes than your sink has, you can buy filler plugs to cover the extra holes. If your new faucet needs more holes, you will need to drill them, which requires a drill and a hole saw bit. Drilling through stainless steel or cast iron is difficult; consider hiring a plumber for this step if you have never done it.

Do I need to replace the supply lines when I replace the faucet?

Not always. If your old supply lines are flexible hoses in good condition, you can reuse them. If they are rigid copper or if they are kinked or cracked, replace them. New supply lines are inexpensive and come in standard sizes; measure the length you need and buy the same diameter as your old lines.

What if water leaks from the base of the faucet where it meets the sink?

This usually means the gasket or putty seal failed. Turn off the water, remove the faucet, clean off the old putty or gasket, and install a new one. If the sink surface is damaged or warped, the faucet may never seal properly; you may need a new sink or a professional repair.