A tub spout with diverter is the fitting that lets you switch water from the tub faucet to the showerhead

The spout itself is the short pipe sticking out of the wall where water comes out when you fill the tub. The diverter is the valve inside or on that spout that redirects water up to the shower when you pull a knob or lift a lever. When the diverter wears out, water leaks from the spout even when you want it going to the shower, or the lever gets stuck. Replacing it is a straightforward job that takes about 30 minutes and requires only a wrench and an adjustable wrench or pliers.

The spout screws onto a threaded pipe stub that sticks out of the wall. You unscrew the old one, clean the threads, and screw on the new one. No soldering, no special tools, and no need to turn off the water to the whole house—the spout itself has no shutoff valve, but you won't be opening any water lines during this job.

Key Takeaways

  • A tub spout with diverter screws directly onto a threaded pipe stub in the wall, so replacement means unscrewing the old one and screwing on a new one.
  • You need to measure the pipe stub diameter (usually 1/2 inch) and the distance from the wall to the end of the spout to order the correct replacement.
  • Teflon tape wrapped around the threads prevents leaks at the connection where the spout meets the wall.
  • If the spout is stuck or corroded, soak it with penetrating oil and use a pipe wrench for leverage rather than forcing it.
  • Test the diverter before you finish by pulling the lever or knob while water runs—it should stop flowing from the spout and go to the shower instead.

Measure the pipe stub and order the right replacement

Before you remove anything, you need to know what size spout to buy. Look at the threaded pipe sticking out of the wall. It is almost always 1/2 inch in diameter, but measure it or bring a photo to the hardware store to be sure. The spout screws onto this pipe, so the hole in the new spout must match.

Next, measure how far the old spout sticks out from the wall. This is called the projection. Measure from the wall surface to the very end of the spout. Common projections are 4 inches, 5 inches, and 6 inches. If you order a spout that is too short, water will spray behind it. Too long, and it will hit the tub rim or look awkward. Write down both measurements—pipe size and projection—before you go shopping.

At the hardware store or online, look for "tub spout with diverter" and filter by the measurements you took. The spout will come with a set screw or a small hex key that holds it to the pipe. Some spouts also come with Teflon tape; if yours does not, buy a roll.

Remove the old spout

Look underneath or behind the spout for a small set screw. This screw holds the spout to the pipe and prevents it from spinning. Use a hex key or screwdriver (depending on the type) to loosen and remove it. Once the set screw is out, the spout should unscrew by hand. Turn it counterclockwise, as you would any threaded fitting.

If the spout is stuck—usually because of mineral buildup or corrosion—do not force it. Spray the base where the spout meets the wall with penetrating oil (such as WD-40 or a similar product) and let it sit for 15 to 20 minutes. Then try again. If it still will not budge, wrap a cloth around the spout to protect the finish, grip it with a pipe wrench, and turn slowly. The cloth prevents the wrench from scratching the chrome or brass.

Once the spout is off, you will see the threaded pipe stub sticking out of the wall. It may have old Teflon tape or plumber's putty on it. Wipe or scrape away any old tape, putty, or corrosion. A clean thread makes a watertight seal with the new spout.

Wrap the threads with Teflon tape

Teflon tape (also called plumber's tape or PTFE tape) is a thin white tape that wraps around threaded connections to prevent leaks. Tear off a piece about 12 inches long. Starting at the base of the threads (closest to the wall), wrap the tape clockwise around the pipe stub three to four times, overlapping each wrap slightly. The tape should cover all the threads.

Teflon tape works by filling tiny gaps in the threads. When you screw the new spout on, the tape compresses and creates a seal. Without it, water can seep out where the spout meets the wall. It is cheap insurance and takes 30 seconds.

Screw on the new spout

Hold the new spout in your hand and align the hole with the threaded pipe stub. Start screwing it on by hand, turning clockwise. Once it is hand-tight, use an adjustable wrench or a pipe wrench to tighten it the rest of the way. Do not over-tighten—you want it snug enough that it does not leak, but forcing it can crack the fitting or strip the threads. A quarter-turn past hand-tight is usually enough.

As you tighten, the spout will rotate toward the wall. Stop when the spout is pointing straight down (or at the angle you want) and is fully seated against the wall. If the spout is not quite in the right position, loosen it slightly, adjust, and tighten again.

Install the set screw and test the diverter

Once the spout is tight and positioned correctly, insert the set screw through the small hole underneath or behind the spout. Tighten it with a hex key or screwdriver until it is snug. This screw locks the spout in place so it cannot rotate or loosen over time.

Now test the diverter. Turn on the water at the tub faucet and let it run from the spout. Then pull the diverter lever or knob. The water should stop flowing from the spout and redirect up to the showerhead. If water still comes out of the spout while the shower is on, the diverter is not sealing properly. This usually means the spout is not tight enough. Turn off the water, tighten the spout another quarter-turn, and test again.

Once the diverter works smoothly and no water leaks from the base of the spout, you are done. Wipe away any water and let the connection dry completely before using the shower.

Troubleshooting a leaky connection or stuck diverter

If water drips from the base of the spout after you have tightened it, the Teflon tape may not be sealing properly. Turn off the water, unscrew the spout, and check the tape. If it is bunched up or torn, remove it, clean the threads again, and wrap fresh tape. Make sure you wrap clockwise—wrapping the wrong direction can cause the tape to bunch as you screw the spout on.

If the diverter lever is hard to move or stuck in one position, the internal valve may be corroded. Some spouts have a removable cartridge or valve that you can soak in vinegar to dissolve mineral buildup. Check the manufacturer's instructions that came with your spout. If the valve cannot be cleaned, you will need to replace the entire spout again.

If water leaks from the spout even when the diverter is pulled all the way, the seal inside the diverter is worn out. This is not something you can repair—the spout must be replaced. The good news is that you now know how to do it.

Frequently Asked Questions

Do I need to turn off the water to replace a tub spout?

No. The spout itself has no shutoff valve, and you are not opening any water lines during the replacement. You can work dry. However, turn on the water briefly to test the diverter when you are finished, so have a towel nearby.

What if the pipe stub is longer than the spout hole?

The pipe stub should be flush with or slightly recessed into the wall. If it sticks out too far, the spout will not screw on far enough to seal. You may need a longer spout or a spout with a larger projection. If the stub is damaged or too long, a plumber can cut and re-thread it, but this is beyond a basic replacement.

Can I use plumber's putty instead of Teflon tape?

Putty works for some connections, but Teflon tape is better for threaded spout connections. Tape is easier to explore, does not dry out, and creates a more reliable seal. Use tape unless the spout instructions specifically call for putty.

How tight should the set screw be?

Tight enough that the spout does not move when you pull the diverter lever, but not so tight that you strip the screw or crack the spout. If you feel strong resistance, stop. The screw is small and can break easily if over-tightened.

What if the diverter still leaks after I have tightened everything?

Check that you wrapped the threads with Teflon tape and that the tape is not bunched. If the spout is tight and the tape is correct, the internal seal of the diverter may be defective. Replace the spout with a new one—defects in the valve itself cannot be fixed by tightening.