What a tub diverter does and when to replace it
A tub diverter is the valve that redirects water from your bathtub spout to your showerhead. When you pull up the knob or lever, it closes off the spout and sends water upward instead. Over time, diverters wear out—water starts leaking from the spout even when the shower is running, or the lever gets stuck and won't stay in the shower position.
Replacing a diverter takes about 30 to 45 minutes if you have basic tools and the right replacement part. The job is straightforward enough for a first-timer, though you will need to turn off your water supply and may need to remove your spout to access the diverter inside the wall.
Key Takeaways
- Turn off the water at the main shut-off valve before you start, then open a faucet elsewhere to release pressure in the pipes.
- The diverter sits inside the wall behind your spout; you will need to remove the spout first by unscrewing it or prying out a set screw.
- Measure your old diverter or bring it to the hardware store to match the exact type and size—diverters are not universal.
- Use plumber's tape on the threaded connections to prevent leaks, and test the water pressure before you close up the wall.
Gather your tools and the correct replacement part
Before you touch anything, you need the right diverter. Diverters come in different styles—some screw directly into the wall, others fit inside a cartridge, and some are built into the spout itself. The easiest way to get the correct part is to remove your old diverter and bring it to a hardware store or plumbing supply shop. A staff member can match it to a replacement.
If you cannot remove the old one first, take a photo of your spout and diverter lever, note the brand if visible, and describe how the lever moves (does it pull up, turn, or slide?). Call ahead to a local plumbing supply store—they often have the knowledge to identify what you need over the phone.
Gather these tools: an adjustable wrench, a screwdriver (flathead and Phillips), plumber's tape (also called PTFE tape or Teflon tape), a bucket or towel to catch water, and possibly a spout removal tool if your spout has a hidden set screw. Many hardware stores loan or rent spout removal tools for free or a small deposit.
Turn off the water and remove the old spout
Locate your main water shut-off valve—usually near the water meter or where the main line enters your house. Turn it clockwise until it stops. Then open a faucet in your kitchen or bathroom to release the pressure still in the pipes. Leave that faucet open while you work.
Look at your tub spout. If you see a small hole on the underside, there is a set screw inside. Use a flathead screwdriver to turn it counterclockwise until it loosens, then unscrew the spout by hand. If there is no hole, the spout is threaded directly into the wall fitting. Wrap a towel around it to protect the finish, then use an adjustable wrench to turn it counterclockwise. It should unscrew like a bolt. Place a bucket underneath—water will drip out.
Once the spout is off, you will see the diverter stem sticking out of the wall. This is what you are replacing.
Remove the old diverter and install the new one
The diverter stem has a nut at the base where it enters the wall. Use your adjustable wrench to hold that nut steady while you unscrew the stem itself by hand or with a wrench. Turn counterclockwise. Once the stem is out, you may see a cartridge or valve body inside the wall—that comes out too, depending on your diverter type. Your replacement part should come with instructions for your specific model; follow those for removal of any internal parts.
Before you install the new diverter, wrap the threaded end with plumber's tape. Wrap it clockwise around the threads three to four times—this creates a watertight seal. Insert the new diverter stem into the wall opening and hand-tighten it first. Then use your wrench to snug it down firmly, but do not overtighten or you risk cracking the fitting inside the wall.
Screw the spout back on by hand first, then tighten it with the wrench if it was originally threaded. If it has a set screw, insert the screw and tighten it with a flathead screwdriver until snug. Do not force it.
Test for leaks before you finish
Turn the main water shut-off valve back on by turning it counterclockwise. Open the faucet you left running to let air out of the pipes, then close it. Now test your new diverter. Turn on the tub spout and let water run for 10 seconds. Then pull the diverter lever to send water to the shower. Watch for drips from the spout—a small drip is normal for the first few seconds, but steady water means the diverter is not sealing properly.
If water keeps running from the spout, turn off the water again and check that the diverter stem is fully tightened. You may also need to wrap additional plumber's tape on the threads. If the problem persists after a second try, the replacement part may be the wrong type for your plumbing setup—take it back and describe the issue to the store staff.
Once the diverter works without leaking, check under the sink and in the wall cavity (if accessible) for any drips from the connections. Wipe up any water and let everything dry for a few hours before you close up the wall or explore caulk around the spout.
Common mistakes that cause leaks
The most frequent error is forgetting plumber's tape on the threaded connections. Without it, water seeps out around the stem where it enters the wall. Even if the diverter itself works, you will see a slow drip that gets worse over weeks.
Another common mistake is buying the wrong diverter type. If your old diverter was a cartridge style and you install a stem style, or vice versa, it will not fit properly and will leak when ready. Always match the exact type and size.
Overtightening the stem can crack the fitting inside the wall, which means you have to cut into the wall to replace it. Tighten firmly until you feel resistance, then stop. You do not need to use all your strength.
When to call a plumber instead
If you turn off the main valve and water still runs from the tub, there may be a secondary shut-off valve for that bathroom that is stuck or broken. A plumber can locate and repair it. If the diverter stem is corroded or stuck and will not budge after soaking with penetrating oil, forcing it can break the fitting—a plumber has specialized tools to remove stuck stems without damage.
If you remove the spout and find the wall fitting itself is cracked or leaking, that requires soldering or replacing the fitting inside the wall. This is beyond a basic replacement and usually requires opening the wall or accessing the plumbing from behind the tub.
Frequently Asked Questions
Can I replace the diverter without turning off the main water valve?
No. Even with the water off, pressure remains in the pipes. Turning off the main valve and opening a faucet releases that pressure safely. If you skip this step, water will spray out when you remove the old diverter, and you risk damaging the new one before it is installed.
What if water leaks from the diverter connection after I install it?
Turn off the water, remove the spout, and check that the diverter stem is fully tightened. If it is, wrap additional plumber's tape around the threads—usually two or three more wraps solve the problem. Reinstall and test again.
How do I know if my diverter is the problem or if something else is leaking?
Turn on the shower and pull the diverter lever. If water continues to pour from the spout instead of stopping, the diverter is worn out. If the spout drips slowly even when the shower is off, the problem is likely a worn spout washer or a different valve, not the diverter.
Do I need a plumber's license to replace a diverter?
No. Replacing a diverter is a basic maintenance task that homeowners can do. You do not need a license. However, if you damage the wall fitting or encounter corroded pipes, a licensed plumber can handle repairs that require soldering or wall access.
How long does a new diverter last?
Most diverters last 10 to 15 years depending on water quality and how often the shower is used. Hard water and frequent use shorten the lifespan. When it fails again, the replacement process is the same.