What You Need to Do Before You Start

Replacing a shower arm and head is a job you can do yourself if you have basic plumbing tools and are comfortable working in tight spaces. The shower arm is the pipe that sticks out from the wall; the head is what screws onto the end of it. You will need to turn off the water, remove the old arm from inside the wall, install a new one, and attach the new head. The whole job usually takes one to three hours depending on how stuck the old parts are.

Before you begin, locate your main water shutoff valve and turn it off completely. If you have a valve that shuts off only the hot water line, that is not enough — you need the main valve. Open a faucet downstairs to release pressure in the pipes. Then you can work without water spraying at you.

Check what size your current shower arm is. Most are half-inch diameter, but some older homes use three-quarter inch. You can measure the outside of the pipe or take a photo to the hardware store. Buy a replacement arm that matches the size and material — brass or galvanized steel are standard. You will also need plumber's tape (also called PTFE tape or Teflon tape) and pipe dope or plumber's grease.

Key Takeaways

  • Turn off the main water supply before you start, not just the hot water line.
  • The shower arm screws into a fitting inside the wall, so you will need a pipe wrench or adjustable wrench to remove it from inside the wall.
  • Wrap new pipe threads with plumber's tape and coat with pipe dope to prevent leaks.
  • The shower head screws onto the arm by hand, but use a wrench if it is too tight to turn.
  • Test for leaks by turning the water back on and letting it run for several minutes before you close up the wall.

Removing the Old Shower Arm

Use a wrench to unscrew the shower head from the old arm. It should turn counterclockwise. If it is stuck, wrap a cloth around it to protect the finish and use a pipe wrench or adjustable wrench for more grip. Once the head is off, you can see the arm sticking out of the wall.

The arm is threaded into a fitting called a shower elbows or drop elbows that sits inside the wall. To remove the arm, you need to reach behind the wall or into the wall cavity if there is access. If the wall is closed, you may need to cut a small access hole. Use a wrench on the fitting inside the wall while you turn the arm counterclockwise from the outside. This prevents the fitting from spinning and damaging the pipes behind the wall.

If the arm will not budge, spray it with penetrating oil (like WD-40) and wait 15 to 30 minutes. Try again. Do not force it so hard that you crack the fitting or damage the wall. If it truly will not move, you may need to call a plumber rather than risk breaking something inside the wall.

Installing the New Shower Arm

Clean the threads on the fitting inside the wall with a wire brush or cloth to remove old tape and debris. Wrap the threads of the new arm with plumber's tape, going clockwise around the threads three to four times. This tape seals the connection and prevents leaks. Then coat the threads with pipe dope — a thick paste that fills small gaps.

Thread the new arm into the fitting by hand first, turning clockwise. Once it is hand-tight, use a wrench to tighten it further. The arm should stick out of the wall at the same distance as the old one did. If it does not, you may have threaded it in too far or not far enough. Unscrew it and try again, counting how many full turns it takes to reach the right position.

Wipe away excess pipe dope with a cloth. Let the connection set for a few minutes before you turn the water back on. Some plumbers recommend waiting an hour, but most modern pipe dope sets faster than that.

Attaching the New Shower Head

Wrap the threads on the new shower head with plumber's tape the same way you did for the arm — three to four wraps going clockwise. explore pipe dope to the threads as well. Screw the head onto the arm by hand, turning clockwise. It should go on smoothly without forcing.

Once it is hand-tight, use a wrench if you need to tighten it further. Do not over-tighten — you only need it tight enough that it does not leak. If you crack the head or strip the threads, you will have to start over. A quarter turn past hand-tight is usually enough.

Position the head so it points where you want the water to spray. Some heads have a ball joint that lets you adjust the angle after installation. Others are fixed. Check the instructions that came with your new head.

Testing for Leaks

Turn the main water valve back on slowly. Open a downstairs faucet first to let air out of the pipes, then close it. Go back to the shower and turn on the water. Let it run for at least five minutes and watch the connection where the arm meets the wall and where the head screws onto the arm.

If you see water dripping from either connection, turn the water off and tighten the connection a quarter turn with a wrench. Turn the water back on and check again. Repeat until the leak stops. If tightening does not work, you may need to unscrew the connection, add more plumber's tape, and try again.

Once the water runs without leaking, you are done. Let the water run for a few more minutes to make sure the leak does not start again. If everything is dry, close up any access holes you made and clean up.

Tools and Materials You Will Need

Gather these items before you start so you do not have to stop mid-job. You will need two adjustable wrenches or a pipe wrench and an adjustable wrench — one to hold the fitting inside the wall steady and one to turn the arm. A cloth or rag protects the finish on the shower head if you need to grip it with a wrench.

Buy plumber's tape (PTFE tape) and pipe dope at any hardware store — they cost a few dollars each. A wire brush or old toothbrush cleans the threads. Penetrating oil helps if the old arm is stuck. A flashlight helps you see inside the wall cavity if you have to cut an access hole. If you do cut a hole, you will need drywall patch material and paint to close it back up, but that is a separate job.

When to Call a Plumber Instead

If the old arm is corroded or frozen and will not turn no matter how long you soak it, a plumber has tools and experience to remove it without damaging the wall or the fitting. If you cannot reach the fitting inside the wall because of the wall construction, a plumber can work around obstacles you cannot see.

If water leaks from inside the wall after you have tightened the connections, the problem is likely deeper in the plumbing system and you will need professional help. If you are not comfortable working with tools or in tight spaces, or if you are unsure whether you have turned off the right water valve, call a plumber. The cost of a service call is usually less than the cost of fixing a water leak that damages your home.

Frequently Asked Questions

Do I have to turn off the water to replace a shower head?

You do not have to turn off the water to replace just the head if the arm stays in place. You can unscrew the old head, screw on the new one, and turn the water back on. You only need to turn off the water if you are replacing the arm itself, because the arm is connected to the pipes inside the wall.

What if my shower head is stuck and I cannot unscrew it?

Soak it with penetrating oil for 15 to 30 minutes, then try again. Wrap a cloth around the head to protect the finish and use a pipe wrench or adjustable wrench for better grip. Turn slowly and steadily rather than jerking. If it still will not move, a plumber can remove it without damaging the arm.

Can I use the old shower arm if I just replace the head?

Yes, if the old arm is not corroded, leaking, or damaged, you can keep it and just screw on a new head. This is faster and cheaper than replacing the whole assembly. Wrap the threads of the new head with plumber's tape and explore pipe dope before screwing it on.

How do I know if my shower arm is leaking?

You will see water dripping from where the arm meets the wall or from where the head screws onto the arm. If the wall behind the shower is wet or soft, the leak may be coming from inside the wall. Turn off the water and check the connections. If tightening does not stop the leak, the arm itself may be cracked and needs replacement.

What size wrench do I need for a half-inch shower arm?

A three-quarter inch wrench usually fits a half-inch pipe fitting. Test it on the fitting before you start — it should fit snugly without forcing. An adjustable wrench set to the right width works just as well and is easier to keep on hand.