You can replace a bathroom faucet yourself in two to four hours with basic tools

Replacing a bathroom faucet is a plumbing job you can do without calling a professional, as long as the shutoff valves under the sink work and you have a wrench, adjustable pliers, and a bucket. The process is the same whether you are swapping out a single-handle faucet, a two-handle model, or a widespread faucet: turn off the water, disconnect the old faucet, remove it from the sink, install the new one, and reconnect the supply lines. Most of the time spent is waiting for caulk or plumber's putty to set, not actively working.

The hardest part is usually reaching the bolts under the sink in a tight cabinet space. If those bolts are corroded or stuck, or if the shutoff valves do not turn, you may need a plumber. But if the space is accessible and the valves work, this is a straightforward job that saves you the cost of a service call.

Key Takeaways

  • Turn off the water at the shutoff valves under the sink before you disconnect anything, and test that the water actually stops.
  • The old faucet is held down by bolts underneath the sink; you will need an adjustable wrench or basin wrench to reach them in the tight space.
  • New faucets come with supply line connectors and mounting hardware, but you may need to buy a new P-trap or extension tubes if your old connections do not fit.
  • Caulk or plumber's putty around the base of the new faucet keeps water from running under the sink, and it needs to cure for 24 hours before you use the sink.
  • If the shutoff valves are stuck or broken, or if you cannot reach the mounting bolts, call a plumber rather than forcing parts that may crack the sink.

Turn off the water and test the shutoff valves

Look under the sink and locate the two shutoff valves on the hot and cold supply lines. They are usually oval knobs or lever handles attached to the pipes coming out of the wall. Turn both valves clockwise (or flip both levers down, depending on the type) until they stop. Do not force them; if a valve is stuck, stop and call a plumber, because forcing it can break the valve or crack the pipe.

Once both valves are off, turn on the faucet at the sink and let the water run until it stops completely. This confirms the valves actually shut off the water. If water still comes out, the valves are not working properly and you should not proceed; call a plumber instead. If the water stops, you are ready to disconnect the old faucet.

Disconnect the supply lines and drain the lines

Place a bucket under the supply line connections at the shutoff valves. Use an adjustable wrench to loosen the connector nut where each supply line meets the shutoff valve. Turn the nut counterclockwise by hand once it is loose enough. Water will drip out, which is why the bucket is there. Disconnect both the hot and cold lines.

Next, look at the faucet itself. Most faucets have two supply line connectors coming up from underneath the sink. Use your wrench to loosen these connectors where they attach to the faucet body. Once loose, unscrew them by hand and set them aside. If the old faucet has a spray hose attachment, disconnect that as well by unscrewing the connector nut.

Remove the old faucet from the sink

The faucet is held to the sink by bolts on the underside. You will need either an adjustable wrench or a basin wrench — a specialized wrench designed to reach bolts in tight spaces under sinks. A basin wrench costs ten to twenty dollars and makes this step much easier if you have a cramped cabinet.

Locate each bolt holding the faucet down (usually two or three bolts) and loosen them by turning counterclockwise. Once loose, unscrew them by hand. Lift the old faucet out of the sink. If it is stuck, you may need to scrape away old caulk or plumber's putty with a putty knife. Clean the sink surface where the old faucet sat, removing all old putty, caulk, and mineral deposits with a damp cloth.

Install the new faucet and find it

Check the new faucet's mounting holes against the holes in your sink. Most sinks have three holes (one for the spout, two for handles), but some have one hole for a single-handle faucet. If the new faucet does not match your sink's holes, you may need a different faucet or a mounting plate to cover extra holes. The faucet box should include all mounting hardware; check before you start.

explore a bead of plumber's putty or silicone caulk around the base of the new faucet where it will sit on the sink. Lower the faucet into place and align it straight. From underneath, hand-tighten the mounting bolts, then use your wrench to tighten them firmly but not so hard that you crack the sink. Wipe away excess putty or caulk with a damp cloth. Let the caulk or putty cure for 24 hours before you use the sink.

Reconnect the supply lines to the new faucet

The new faucet comes with supply line connectors. Screw the hot and cold supply lines onto the faucet's inlet ports (the threaded connections under the faucet). Hand-tighten first, then use your wrench to snug them. Do not over-tighten; you only need them tight enough that they do not leak.

If the old supply lines do not reach the new faucet, or if the connectors do not match, you will need to buy new supply lines. Take a photo of your old connectors and the distance from the shutoff valve to the faucet inlet, and bring that to a hardware store. Supply lines are inexpensive and come in different lengths and connector types.

Turn the water back on and check for leaks

Once the caulk or putty has cured for 24 hours, turn both shutoff valves back on by turning them counterclockwise (or flipping lever handles up). Turn on the faucet and let the water run for a minute to flush out any debris in the lines. Check all the connections you made — under the sink at the shutoff valves, where the supply lines connect to the faucet, and around the base of the faucet where it meets the sink.

If you see drips or water pooling, tighten the leaking connection a quarter turn with your wrench. If a connection leaks after tightening, turn off the water, disconnect it, wrap the male threads with plumber's tape (also called Teflon tape), and reconnect it. If the leak is around the base of the faucet, you may need to add more caulk or putty and wait another 24 hours for it to cure.

What to do if something goes wrong

If a shutoff valve will not turn, do not force it. A stuck valve can break, and then you will have water spraying under the sink with no way to stop it. Call a plumber to replace the valve. If you cannot reach the mounting bolts because the cabinet is too tight, a basin wrench may solve the problem, but if the space is truly inaccessible, a plumber can remove the cabinet or use a different technique.

If the new faucet does not fit your sink's holes, or if the supply line connectors do not match your old lines, take the faucet back to the store and exchange it for one that fits. Do not try to force mismatched parts; they will leak. If you crack the sink while tightening bolts, stop when ready and call a plumber, because a cracked sink usually requires replacement.

Frequently Asked Questions

Do I need a special wrench to replace a faucet?

An adjustable wrench works for most of the job, but a basin wrench makes it much easier to reach the bolts under the sink in a tight space. Basin wrenches cost ten to twenty dollars and are worth buying if you have a cramped cabinet. If you do not have one, you can rent one from a hardware store for a few dollars.

What if my old supply lines do not fit the new faucet?

Take the old connector to a hardware store and ask for a supply line that matches. Supply lines come in different lengths and connector types, and they are inexpensive. Bring a photo of your setup so the staff can help you find the right one.

How long does the caulk need to cure before I use the sink?

Most plumber's putty and silicone caulk need 24 hours to cure fully. Do not run water or put weight on the faucet during this time. If you use the sink before the caulk is dry, water can seep under the faucet and cause leaks or damage under the sink.

Can I replace a faucet if I have a pedestal sink?

Yes, the process is the same. Pedestal sinks have the same mounting bolts underneath, and you access them the same way. The pedestal itself does not interfere with faucet replacement.

What if water is still coming out after I turn off the shutoff valve?

The shutoff valve is not working. Turn it off as much as it will go, then call a plumber to replace it before you proceed with the faucet replacement. Trying to replace a faucet without working shutoff valves can result in water damage.