How to Replace a Bathtub Faucet

Turn off the Main Building Shut off Valve

In order to perform almost any plumbing repair in the home, you will need to turn off the water to prevent leaks, flooding, and blow-offs while you work. Locate the main building shut-off valve, which is typically found in the basement or the mechanical room.

Turn off the water and open the faucet on the laundry sink or a basement bathroom sink in order to drain most of the water out of the system. It's also recommended to turn on the sink faucet and bathtub faucet to drain any water that is trapped in these pipes.

Lay a Towel or Drop Cloth in the Bottom of the Tub

When replacing the bathtub faucet, you will need to remove and handle one or more screws. By placing a towel or drop cloth in the bottom of the tub, you can prevent these small fittings from accidentally falling into the drain. It's also a good idea to have a safe location outside of the tub where the fittings can be kept until they are needed for reinstallation.

Remove the Handle Index from the Stem

Start the process of replacing the faucet by using a flathead screwdriver to pry the index off of the handle stem. The index is the small plastic or metal circle that sits in the center of the handle to prevent access to the fastener. If you carefully pry up on each side of the index, you can remove it from each handle without chipping or cracking. However, if you put too much force into your attempt you can break the index, though this may not matter if your new faucet replacement kit comes with a new handle and index.

If your bathtub faucet has more than one handle, then repeat the process to remove the index from the second handle. This should leave the fastener exposed so that the entire handle can be taken off.

Loosen the Handle Fastener to Remove the Handle

Use a flathead or Phillips screwdriver to loosen the screw that was underneath the index. If it seems seized, don't keep trying to turn it with the screwdriver, as this will likely strip the screw. Instead, treat the screw with a lubricating solution, like WD-40.

Turn the screw counterclockwise until it can be completely removed, then set the screw aside in a safe place until it's needed for reinstallation. The handle should now slide off of the stem without much effort. If you have a second handle, repeat the process to remove the screw and handle.

Unscrew the Stem From the Faucet

After removing the handle, you should see a thin pipe that extends out from the wall. This is known as the stem, and it's responsible for controlling the faucet. The stem can be removed with a pass-through socket wrench that can extend over the stem and grip the hex nut. With the socket wrench in place, turn the nut counterclockwise to loosen the stem. Once the stem is loosened, simply grab it with your hand and pull it out of the wall. Repeat the process for each handle in the bathtub faucet setup, and put the old parts aside so that they can be used as a reference to purchase compatible replacement parts.

Remove the Spout

The spout on a bathtub faucet is either secured with a mounting screw that is usually located on the underside of the spout, or it is simply screwed onto the pipe. Check for a mounting screw and if there is one, then use a hex key or screwdriver to remove the screw and put it aside in a safe location for reinstallation. By pulling on the spout, it should slide right off the pipe without a problem.

If the spout does not have a mounting screw, then you will need to wrap a cloth or towel around the spout to protect the metal before gripping it with a pipe wrench and turning the entire spout counterclockwise to remove it from the pipe. Once the spout is loosened, it should slide off, revealing the water pipe that was inside the spout.

Measure the Pipe and Purchase Replacement Parts

To ensure that you get compatible parts for your current plumbing set, use a tape measure to measure the length of the pipe. You will need to get a replacement spout that is longer than the pipe. Use the old handles, stems, and spout as a reference when you head to your local hardware store to pick up replacement parts.

Remember, if the shower has a multi-handle setup, you can't switch to a single-handle setup without a significant amount of re-plumbing, so it's best to invest in a similar set of handles, rather than picking up a replacement handle that won't work with the existing plumbing.

Screw in a New Stem

With all of the new parts ready to go, you can begin to reinstall the new bathtub faucet. Start by feeding the threaded end of the stem into the hole where the old stems were previously installed. Turn the stem clockwise, tightening it by hand at first, then use a socket wrench to ensure that the connection is snug and secure. Just make sure that you don't over-tighten the stem, because this can cause damage to the pipes. If your bathtub has multiple handles, repeat the process with each handle to install the new stems.

Install the New Handles

The handle is easy enough to reinstall. Simply slide it over the new stem until the handle touches the wall. Once in place, use a flathead or Phillips screwdriver to secure the handle with the old screw that you removed or with a new screw if one came with your bathtub faucet replacement kit. The index cover should pop into place with a little push in order to protect the screw and finalize the look of the handle.

If you have more than one handle in the bathtub, repeat the process with each handle. You may also want to use a caulk gun to caulk around the base of each handle for the purpose of preventing water from entering the walls.

Install the New Spout

Before installing the spout, use plumbers' tape on the pipe's threading to help create a secure seal and prevent leaks. If the pipe doesn't have threads, then it may be beneficial to use plumbers grease on the pipe to help lubricate and protect the fitting.

Slide the new spout over the pipe and secure the spout to the pipe with the mounting screw. If your spout doesn't have a mounting screw, then simply turn it clockwise to screw the entire spout onto the pipe. Wrap the spout in a cloth or towel to prevent accidentally scratching the new fixture, then finish tightening the spout with a pipe wrench. Just make sure that the spout is snug against the wall and that it is facing down.

Use a caulk gun and caulk to seal the base of the spout in order to prevent water from entering the walls and causing water damage and mold growth.

Turn on the Water and Test

Turn on the water to the home and allow it to flow throughout the plumbing system. The water will initially push any air out of the pipes, so give it a few minutes before turning off the laundry sink or basement bathroom sink, then proceed to the bathtub.

Check the bathtub faucet and handles for any leaks, then turn off the bathtub faucet and check again with the fixture under pressure. If all went as planned, you should have a new bathtub faucet and no leaks.