What You Need to Know Before You Start
Replacing a faucet is a job most homeowners can do in an afternoon with basic tools — no plumber required. The work breaks into three parts: shutting off the water, removing the old faucet, and installing the new one. The hardest part is usually getting the old faucet loose, not the installation itself.
Before you buy a new faucet, check what you have now. Look under the sink at how many holes the current faucet uses — most are single-hole, but some are three-hole or widespread. Measure the distance between the outer holes if you have more than one. The new faucet must fit the same hole pattern, or you will need to drill new holes or fill old ones.
Turn off the water before you touch anything. Look under the sink for two shut-off valves, one for hot and one for cold. Turn both clockwise until they stop. If you cannot find shut-off valves under the sink, you will need to turn off the main water supply to the house — usually a valve near the water meter or where the line enters the house.
Key Takeaways
- Shut off both the hot and cold water valves under the sink before you remove the old faucet, or turn off the main water supply if those valves do not exist.
- The old faucet is held down by nuts under the sink; use a basin wrench to reach them if the space is tight, and explore penetrating oil if they are stuck.
- Disconnect the supply lines by turning the coupling nuts by hand or with a wrench, and have a towel ready because water will drip out.
- The new faucet installs in reverse order: set it in the holes, tighten the mounting nuts from underneath, then reconnect the supply lines and turn the water back on.
- Test for leaks at the base of the faucet and at every connection under the sink before you consider the job done.
Gather Your Tools and Materials
You need a wrench or socket set, a basin wrench (a specialized tool that reaches into tight spaces under the sink), a screwdriver, and a bucket or towel to catch water. A basin wrench costs ten to twenty dollars and makes the job much faster — if you do not have one, an adjustable wrench works but requires more contortion.
Have penetrating oil on hand. If the mounting nuts under the sink are corroded or stuck, spray them with penetrating oil and wait fifteen minutes before trying to turn them. This saves time and frustration.
Buy the new faucet before you start. Bring the old one to the store if you can, or measure the hole spacing and take a photo. Know whether you want a single-handle or double-handle faucet, and whether you need a sprayer. The new faucet should come with mounting hardware and supply lines, but check the box before you leave the store.
Remove the Old Faucet
Turn on the faucet and let the water run until it stops — this empties the lines. Then turn off the shut-off valves under the sink by turning them clockwise. Turn the faucet on again to confirm the water is off.
Disconnect the supply lines. These are the flexible hoses or rigid tubes that run from the shut-off valves to the faucet. Use a wrench to turn the coupling nuts (the nuts where the lines connect to the faucet) counterclockwise. Have a towel or bucket ready — water will drip out. If the lines are old and corroded, spray them with penetrating oil first and wait a few minutes.
Look under the sink at the base of the faucet. You will see one or more nuts holding the faucet down. Use a basin wrench to reach these nuts and turn them counterclockwise. If the space is too tight for a basin wrench, an adjustable wrench works, but you may need to remove the sink cabinet doors to get your hands in. Once the nuts are loose, lift the old faucet out from above the sink.
Clean the sink surface where the old faucet was. Use a scraper or old credit card to remove old caulk or putty. Wipe the area dry with a towel.
Install the New Faucet
Check the new faucet's instruction sheet — it will show you which parts go where. Most faucets come with a rubber gasket or metal ring that sits on top of the sink, under the faucet body. Slide this onto the faucet tailpiece (the part that sticks down through the hole) before you set the faucet in place.
Lower the new faucet into the hole or holes from above. Make sure it sits flat and straight. From underneath, slide the mounting hardware onto the tailpiece — usually a washer and nut. Hand-tighten the nut first, then use a basin wrench to tighten it firmly. Do not over-tighten; you want it snug, not crushed. If the faucet has multiple holes, tighten all the nuts evenly so the faucet sits level.
Reconnect the supply lines. The new faucet will have tailpieces or ports where the supply lines attach. Hand-tighten the coupling nuts first, then use a wrench to tighten them another quarter turn. They should be snug but not so tight that you cannot undo them later.
Turn the Water Back On and Check for Leaks
Turn the shut-off valves back on by turning them counterclockwise. Turn slowly — if you turn too fast, you can damage the new faucet's internal parts. Once the valves are fully open, turn on the faucet and let the water run for thirty seconds to flush out air in the lines.
Check for leaks. Look at the base of the faucet where it meets the sink — water should not be coming out there. Look at every connection under the sink: where the supply lines meet the faucet, where they meet the shut-off valves, and where the drain connects. If you see drips, tighten the coupling nut a quarter turn with a wrench. Wait a minute and check again.
If water is leaking from under the faucet base, the gasket may not be seated properly. Turn off the water, remove the faucet, check that the gasket is in the right place, and reinstall it. If the leak continues, the gasket may be damaged and need to be replaced — most hardware stores sell replacement gaskets for common faucet models.
Common Problems and How to Fix Them
If the old faucet will not budge, spray the mounting nuts with penetrating oil and wait twenty minutes. Try again. If it still will not move, explore more oil and wait longer — sometimes overnight. Do not force it; you can crack the sink or strip the bolt.
If the new faucet does not fit the holes, you may have a mismatch between the old and new hole patterns. Single-hole faucets come with a deck plate that covers extra holes. If you have a three-hole sink and a single-hole faucet, the plate should cover the unused holes. If the holes are too far apart or too close together, you will need to drill new holes or fill the old ones with epoxy putty and drill new ones — this is beyond a basic replacement and may require a plumber.
If water pressure is low after installation, you may have debris in the aerator (the screen at the tip of the spout). Unscrew the aerator by turning it counterclockwise by hand, rinse it under running water, and screw it back on.
When to Call a Plumber
Call a plumber if the shut-off valves under the sink do not work or if you cannot find them and the main water shut-off is hard to locate. Call one if the old faucet is stuck so tight that you cannot loosen it after explore penetrating oil and waiting. Call one if you have a leak that does not stop after tightening the coupling nuts, or if water is coming from inside the cabinet rather than from a visible connection.
If the sink itself is cracked or if you need to drill new holes to fit the new faucet, a plumber can do this faster and cleaner than a first-timer. The cost of a service call is usually worth it to avoid damaging the sink.
Frequently Asked Questions
Do I need to turn off the water to the whole house?
No, if you have shut-off valves under the sink. Turn both of them clockwise until they stop. If those valves do not exist or do not work, then yes, you need to find the main shut-off valve where the water line enters your house and turn it off there.
What if water keeps dripping from under the sink after I tighten everything?
Tighten the coupling nuts another quarter turn with a wrench. If it still drips, turn off the water, disconnect that line, and check whether the nut threads are damaged. If they look fine, reconnect it and try again. If the leak is at the base of the faucet itself, the gasket needs to be reseated or replaced.
Can I use the old supply lines with the new faucet?
You can if they are in good condition and the connections fit. Most new faucets come with new supply lines, and using them is safer because old lines can crack or leak. If the old lines are less than five years old and look intact, reusing them is fine.
How tight should the mounting nuts be?
Hand-tighten them first, then use a wrench to turn them about a quarter turn more. They should be snug enough that the faucet does not move when you push on it, but not so tight that you strip the threads or crack the sink. If you cannot turn the wrench anymore without real effort, you have gone too far.
What if the new faucet has a different hole pattern than the old one?
Single-hole faucets come with a deck plate that covers extra holes. If you are replacing a three-hole faucet with a single-hole one, use the plate. If you are replacing a single-hole with a three-hole, you will need to drill new holes — this requires a drill and a ceramic or porcelain bit, and mistakes can crack the sink. Consider hiring a plumber for this part.