How to Fix a Shower Leak With Plaster Walls

Find the access panel to the shower plumbing. The access panel is usually in a closet in the room adjacent to the shower plumbing wall. Remove the access panel and look for the two water shut-off valves.

Dry the pipes as much as possible with a dry towel. You first need to determine where the leak originates. Ask a helper to turn on the shower while you shine a flashlight on the shower plumbing to look for the leak. Chances are the leak is where the shower arm connects to the plumbing pipe. If the leak is anywhere other than the shower arm connection, contact a plumber to make repairs, as other repairs are out of scope for the average homeowner.

Turn off the water supply valves and go into the bathroom. Lay a sheet or several towels in the bottom of the tub or shower. It is necessary to get inside the tub or shower, and the sheet protects the surface.

Wrap masking tape around the shower arm 4 inches away from the shower wall. The tape protects the finish of the shower arm when removing it from the shower plumbing.

Lock a pair of vise grips around the tape and shower arm. Adjust the vise grips as necessary so they securely grip the arm without bending it. Hold the arm with your hand close to the wall. Turn the shower arm counterclockwise with the vise grips. Continue turning the arm until it unthreads completely from the shower plumbing pipe.

Shine a flashlight inside the hole where the arm enters the shower wall and inspect the plumbing. Look for signs of corrosion. Remove any residual plumber's tape from inside the threads of the arm connection with a small toothbrush. Most often the leak is due to plumber's tape that fails. If there is corrosion on the house plumbing pipe, a plumber is necessary to replace the plumbing up to the valve.

Clean off the threads at the end of the shower arm. This is the most likely cause of the leak if there is no corrosion on the house pipe. Wrap new plumber's tape around the threads in a clockwise direction. This keeps the tape firmly in the threads when you reconnect the shower arm.

Thread the shower arm into the shower plumbing pipe in a clockwise direction until you can no longer turn it by hand. Turn the shower arm with the vise grips until the shower head is pointing downward.

Turn on the water supply and have your helper turn on the shower once again. Shine a flashlight around the shower arm connection to the shower plumbing and verify there are no more leaks.