What you're replacing and why it matters

A bathtub spout with a built-in shower diverter is the fitting that water comes out of when you turn on the tub, and it has a small lever or knob that redirects water up to the showerhead. When that spout leaks, drips constantly, or the diverter stops working (water won't stay diverted to the shower), replacement is usually the simplest fix. The spout screws or slides onto the pipe stub that sticks out of your wall, and you can remove and install a new one in about 20 minutes with basic tools.

The reason to replace rather than repair is cost and durability. A new spout costs $15 to $40, while a plumber's service call runs $150 to $300. The diverter mechanism inside the spout wears out and cannot be rebuilt—once it fails, the whole spout needs to go.

Key Takeaways

  • Most bathtub spouts screw onto the pipe stub behind the wall, held in place by an internal setscrew or a threaded connection you can access from underneath.
  • You will need an adjustable wrench, a screwdriver, and possibly a spout removal tool (a straightforward metal sleeve that costs $5 to $10) to unscrew the old one without damaging the wall.
  • Measure the diameter of the pipe stub and the distance from the wall to the end of the old spout before you buy a replacement, because spout sizes vary.
  • Wrap plumber's tape (also called thread seal tape or PTFE tape) around the threads of the new spout before screwing it on to prevent leaks at the connection.
  • If the spout is soldered or glued to the pipe, or if you cannot turn it by hand after removing the setscrew, stop and call a plumber rather than risk cracking the pipe inside the wall.

Identify how your spout is attached

Before you buy a replacement, you need to know whether your spout is held on by a setscrew (the most common type) or by a threaded connection. Look underneath the spout where it meets the wall. If you see a small screw head pointing downward or to the side, that is a setscrew—loosen it with a screwdriver and the spout will slide off the pipe stub. If there is no visible screw, the spout is threaded on, and you will need to unscrew it by turning it counterclockwise.

Some spouts have both: a setscrew that locks the spout in place after it is threaded on. In that case, remove the setscrew first, then unscrew the spout itself. The setscrew is usually small and brass or stainless steel, and it may be hidden under a decorative cap or escutcheon (the trim ring around the spout).

Remove the old spout

For a setscrew spout: Use a screwdriver that fits the screw head snugly—a Phillips or flathead, depending on the screw. Turn counterclockwise until the screw is loose enough that you can pull the spout straight out toward you. It should slide off the pipe stub with gentle pressure. If it is stuck, spray penetrating oil (like WD-40) around the base where the spout meets the wall, wait 10 minutes, and try again.

For a threaded spout: Use an adjustable wrench to grip the spout near the wall and turn it counterclockwise. If the spout is tight or the wrench slips, use a spout removal tool—a hollow metal sleeve that slides over the spout and gives you more grip. Wrap a cloth around the spout first to protect the finish from the wrench. Turn slowly and steadily; if you feel strong resistance, stop and explore penetrating oil rather than forcing it, which can crack the pipe inside the wall.

Once the spout is off, you may see old plumber's tape or pipe dope (a putty-like sealant) on the threads. Wipe it away with a cloth or old toothbrush so you can see the pipe clearly and explore fresh tape to the new spout.

Measure the pipe and choose a replacement

The pipe stub sticking out of the wall is usually either 1/2 inch or 3/4 inch in diameter. Measure it with a ruler or calipers. Also measure how far the old spout stuck out from the wall—this is called the projection, and it typically ranges from 4 to 6 inches. Write both measurements down when you go to buy the new spout, because they determine which model will fit.

Spouts come in two main types: slip-fit (held on by a setscrew) and threaded (screwed on). If your old spout was slip-fit, you can replace it with another slip-fit spout of the same diameter. If it was threaded, buy a threaded replacement. Most hardware stores and online retailers list the pipe size and projection in the product description, so you can match them exactly.

Look for a spout that includes a diverter rated for your water pressure. Standard residential water pressure is 40 to 80 pounds per square inch (psi); the spout packaging will say if it is rated for that range. Avoid the cheapest options, which often have diverters that stick or fail within a year or two.

Install the new spout

Wrap the threads of the new spout with plumber's tape (also called PTFE tape or thread seal tape). Wrap it clockwise around the threads three to four times, stretching it slightly as you go. This tape seals the connection and prevents leaks. If the spout came with pipe dope instead, explore a thin layer to the threads with your finger.

For a threaded spout: Screw it onto the pipe stub by hand first, turning clockwise until it is snug. Then use the wrench to turn it another quarter turn or so until it is tight against the wall. Do not over-tighten—you want it firm, not cranked down hard, which can crack the fitting or strip the threads.

For a slip-fit spout: Slide it onto the pipe stub until it is flush against the wall, then insert the setscrew from underneath and tighten it with a screwdriver. The screw should be snug but not so tight that you strip it.

Test the diverter and check for leaks

Turn on the water at the tub faucet and let it run for a few seconds. Then pull or turn the diverter lever to redirect water to the showerhead. The water should switch cleanly with no dripping from the spout. If water still comes out of the spout while the shower is running, the diverter is not sealing properly—this usually means the spout is not tight enough or the diverter mechanism is faulty.

If the spout is not tight enough, turn off the water, use the wrench to tighten it another quarter turn, and test again. If water still leaks from the spout after tightening, the new spout may be defective. Return it and try a different brand or model. If the spout is tight and the diverter still does not work, the spout itself is faulty and needs to be replaced under warranty or with a different unit.

Check underneath the spout where it meets the wall for drips. A small amount of moisture is normal for the first few hours as the tape settles, but steady dripping means the connection is not sealed. Turn off the water, remove the spout, add more plumber's tape, and reinstall it.

When to call a plumber instead

If the old spout will not budge after you have applied penetrating oil and waited, or if you hear cracking sounds when you try to turn it, stop when ready. Forcing a stuck spout can break the pipe inside the wall, which requires cutting into the wall to repair. A plumber has specialized tools and experience to remove stuck spouts without damage.

If the pipe stub is corroded, cracked, or leaking from the wall itself (not from the spout connection), the problem is inside the wall and beyond a straightforward spout replacement. A plumber can assess whether the pipe needs repair or replacement.

If you are uncomfortable working with plumbing connections or do not have an adjustable wrench and screwdriver, a plumber can do this job quickly and will stand behind the work if the diverter fails.

Frequently Asked Questions

Can I replace a spout with a diverter if my tub currently has a spout without one?

Yes. A spout with a diverter screws on the same way as a spout without one, and the pipe stub does not need to be changed. You will need to run a new water line from the spout up to the showerhead if you do not already have one, which usually requires a plumber to cut into the wall and install the pipe and showerhead.

What is the difference between a diverter spout and a separate diverter valve?

A diverter spout has the lever built into the spout itself and is the simplest and cheapest option. A separate diverter valve is installed higher up on the wall and controls water flow to both the spout and showerhead independently. Separate valves are more durable and give you more control but cost more and require more plumbing work to install.

Why does my new spout still drip from the diverter after I installed it?

The most common cause is that the spout is not tight enough on the pipe. Use the wrench to tighten it another quarter turn and test again. If it still drips, the diverter seal inside the spout may be defective—this is rare with new spouts but does happen. Return the spout and try a different model or brand.

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

No, because the spout is downstream of the main shutoff and there is no valve between the pipe stub and the spout itself. Water will drip from the pipe stub while you work, so have a towel or bucket ready. If you want to avoid the drip entirely, you can shut off the water at the main valve, but it is not necessary.

Can I use plumber's tape on a slip-fit spout?

No. Plumber's tape is only for threaded connections. Slip-fit spouts connect by sliding onto a smooth pipe stub and are held in place by the setscrew, which compresses the spout against the pipe. Tape on a slip-fit connection will not help and may prevent the spout from seating properly.