Shower Arm — Pipe Sizes, Types, and How to Replace

A shower arm is the short curved or straight pipe that extends from the wall or ceiling supply stub-out to support and position the showerhead.

Shower Arm diagram — labeled parts, dimensions, and installation context

What It Is

The shower arm threads onto the half-inch IPS supply nipple inside the wall and projects outward and downward to bring the showerhead out over the shower floor. It carries the full water supply from the wall connection to the showerhead and also bears the weight of the showerhead and any extension arm or slide bar attached to it.

Most residential shower arms are made from chrome-plated brass or stainless steel. The standard arm is an S-curve or J-curve that positions the showerhead roughly 6–8 inches from the wall at a slight downward angle. The connection at the wall end and the showerhead end both use standard half-inch NPT male threads.

Types

Standard curved arms (also called goose-neck arms) project out from the wall and angle down toward the showerhead. Straight or angled arms project at a flatter angle for a more modern look. Ceiling-mount drop arms connect to ceiling supply stubs and drop straight down to a rain shower head. Extension arms thread onto an existing standard arm to increase reach or height.

Where It Is Used

Shower arms are used in all showers and bathtub tub-shower combinations equipped with a wall-mounted showerhead. They are also used on ceiling-mount rain shower installations with a longer drop arm.

How to Identify One

The shower arm is the pipe between the wall escutcheon (flange cover) and the showerhead. On a standard installation it is roughly 6–12 inches long and curves slightly downward. The shower flange is the separate cover plate that conceals the wall opening behind the arm.

Replacement

Shower arms are replaced when they corrode, develop pinhole leaks at the threads, or when a homeowner wants a different arm length, finish, or style to match a new showerhead. Replacement is usually straightforward — unscrew the old arm counterclockwise, wrap the threads of the new arm with thread tape, and thread it into the wall stub-out.

Shower Arm — FAQ

How do I remove a shower arm that is stuck?

Wrap the arm close to the wall with a cloth to protect the finish, then grip it with a pipe wrench or adjustable pliers and turn counterclockwise. If the arm spins freely without loosening, the supply nipple inside the wall may be turning with it. You will need to open the wall from the back side or use a nipple extractor to hold the nipple stationary.

What thread size is a shower arm?

Standard shower arms use half-inch NPT (National Pipe Thread) on both ends — the wall connection and the showerhead connection. This is universal across US residential plumbing, meaning any standard showerhead will thread onto any standard shower arm without adapters.

How long should a shower arm be?

Standard shower arms are 6–11 inches long. The right length depends on where you want the showerhead positioned relative to the shower floor and the user's height. Extension arms are available in 6-inch to 24-inch extensions to raise or move the showerhead without replumbing the wall.

Why is my shower arm leaking at the wall?

The most common cause is deteriorated or missing thread tape (PTFE tape) on the threaded connection inside the wall. Turn off the water supply, unscrew the arm, clean the threads on the supply nipple, wrap 3–4 layers of thread tape clockwise around the nipple threads, and reinstall the arm. If the supply nipple itself is cracked or corroded, it must be replaced.

Can I install a ceiling rain shower without replumbing?

In some cases, yes. If the wall supply stub-out is high enough, an S-arm or ceiling-adapter arm can route the supply up and over to a ceiling position without opening walls. However, if the stub-out is at standard height (roughly 78–80 inches) the arm will run exposed along the wall and ceiling, which may or may not be acceptable aesthetically.