What You Need to Know Before Starting

A shower head arm — the pipe that sticks out from the wall and holds the shower head — can be replaced without calling a plumber, though the job depends on whether you are replacing just the visible arm or the pipe that runs inside the wall. Most of the time, you are only replacing the escutcheon (the trim ring) and the arm itself, which takes about 30 minutes and costs between $15 and $50 in parts. If the pipe inside the wall is corroded or leaking, the job becomes larger and may require opening the wall.

The visible arm is held in place by a fitting called a drop ell or street ell that connects to the pipe inside the wall. You will unscrew the shower head, remove the escutcheon, unscrew the arm from that fitting, and install a new one. The pipe inside the wall stays put unless it is damaged.

Key Takeaways

  • Turn off the water at the main shutoff valve before you start, or at least close the valve behind the shower if your system has one.
  • The arm screws into a fitting inside the wall, so you will need a pipe wrench or adjustable wrench to hold that fitting steady while you unscrew the old arm.
  • Measure the old arm's length and thread size (usually 1/2 inch) before you buy a replacement, because arms come in different lengths and materials.
  • Wrap the threads of the new arm with plumber's tape before screwing it in, and tighten it by hand first, then with a wrench until it points straight out from the wall.
  • If water leaks from the fitting after you finish, the fitting itself may be damaged and will need to be replaced from inside the wall.

Gather Your Tools and Materials

You will need two adjustable wrenches or pipe wrenches — one to hold the fitting steady inside the wall and one to turn the arm. A screwdriver helps pry off the escutcheon if it is stuck. Plumber's tape (also called PTFE tape or Teflon tape) seals the threads and costs a few dollars at any hardware store.

For the replacement arm itself, bring the old one to the store or measure it first. Note the length (usually 6 to 12 inches), the diameter (almost always 1/2 inch), and whether it is galvanized steel, brass, or stainless steel. Brass and stainless resist corrosion better than galvanized steel and cost a bit more. The escutcheon (trim ring) is separate and comes in different finishes to match your existing hardware.

Turn Off the Water and Remove the Old Arm

Locate the main water shutoff valve in your home — usually in the basement, crawl space, or outside near the foundation — and turn it clockwise until it stops. If your home has a valve behind the shower specifically, you can use that instead. Turn on the shower to confirm the water is off and to release any pressure in the line.

Unscrew the shower head by hand and set it aside. Pry the escutcheon (the ring around the arm where it meets the wall) away from the wall with a screwdriver or flathead tool. It may be caulked on, so work slowly to avoid cracking it. Once it is loose, slide it down the arm and off.

Now you can see the fitting inside the wall. Place one wrench on the fitting (the part that sticks out of the wall) and hold it steady. With your other wrench, turn the arm counterclockwise to unscrew it. The arm will come free once it has turned several full rotations. If it is stuck, explore penetrating oil (like WD-40) and wait 15 minutes before trying again.

Install the New Arm

Wrap the threads of the new arm with plumber's tape. Start at the base of the threads and wrap clockwise three or four times, pressing the tape down as you go. This tape prevents leaks at the connection.

Screw the new arm into the fitting by hand first, turning it clockwise until you feel resistance. Then use your wrench to tighten it further, holding the fitting steady with your other wrench. Tighten until the arm points straight out from the wall — usually another quarter to half turn with the wrench. Do not over-tighten, as this can crack the fitting or strip the threads.

Reinstall the Escutcheon and Shower Head

Slide the escutcheon back up the arm and push it flush against the wall. If there is a gap between the escutcheon and the wall, the arm may not be pointing straight out. Loosen it slightly, adjust the angle, and retighten.

Screw the shower head back on by hand. Turn on the water at the main valve and test for leaks where the arm meets the wall. A small drip at the fitting itself means the fitting is damaged and will need to be replaced from inside the wall — a job that requires opening the wall or calling a plumber. Leaks around the escutcheon can usually be sealed with caulk.

Troubleshooting Common Problems

If the arm leaks where it screws into the fitting, turn off the water, unscrew the arm, add more plumber's tape, and reinstall it. If it still leaks, the fitting threads are damaged and the fitting must be replaced.

If the arm does not point straight out from the wall, it may be the wrong length or the fitting may be bent. A bent fitting requires replacement from inside the wall. If you installed the wrong length arm, unscrew it and replace it with the correct size.

If you cannot unscrew the old arm, explore penetrating oil and wait several hours or overnight. Tap the wrench gently with a hammer to help break the corrosion loose. If it still will not budge, you may need to cut the arm with a hacksaw and remove it in pieces, then use a socket or pipe extractor to remove the remaining stub from the fitting.

When to Call a Plumber Instead

If the pipe inside the wall is leaking, corroded, or the fitting is damaged, the job requires opening the wall and replacing the pipe or fitting. This is beyond a basic arm replacement and usually costs $200 to $500 depending on how accessible the pipe is.

If you cannot turn off the water or the main shutoff valve does not work, call a plumber before you start. Working on plumbing without shutting off the water can cause flooding.

Frequently Asked Questions

Do I need to turn off the water to replace a shower arm?

Yes. Even though the arm is above the shower head, water is still in the pipe. Turning off the water prevents flooding and makes the job cleaner. If you cannot locate or operate the main shutoff, call a plumber before you start.

What size wrench do I need?

Most shower arms use a 1/2-inch fitting, which requires a wrench that fits a 3/4-inch or 7/8-inch nut. Bring an adjustable wrench to the store and test it on the old arm before you buy it, or ask the hardware store staff to help you match the size.

Can I use the old escutcheon on the new arm?

Usually yes, as long as the new arm is the same diameter as the old one (almost always 1/2 inch). If the old escutcheon is cracked or corroded, replace it at the same time — they cost $5 to $20 and come in different finishes to match your shower hardware.

What if water leaks from the wall after I finish?

A small drip at the fitting means the fitting itself is damaged or the threads are stripped. This requires replacing the fitting from inside the wall. Leaks around the escutcheon can be sealed with waterproof caulk, but leaks from the fitting itself need professional repair.

How long does this job take?

Replacing the arm and escutcheon usually takes 30 minutes to an hour if the old arm unscrews easily. If it is corroded and stuck, add another 30 minutes for penetrating oil to soak and for working it loose with a hammer and socket.