If you notice water leaking from the arm or pipe leading to the shower head, you might have a leak in the shower head pipe or joint. The method of repairing the link will depend on the cause and its location.
Before you start cutting holes in your shower wall, look for the obvious. First, make sure the shower head is tightened to the arm. Then make sure the arm is securely tightened. If it’s loose or there is any play, simply tightening them can do the trick.
If you’re certain everything is tight, you might need to remove the shower head and arm. Sometimes, you can repair leaks at the joints by applying pipe compound or a few layers of Teflon tape (in a clockwise manner) around the threads. It’s a simple step that plumbers always use to avoid leaks and ensure tight seals in joints.
If the above measures don’t work, your shower arm might be corroded. The best repair in that case is to replace it. First unscrew the arm from the elbow of the pipe behind the shower wall and reattach a new one, using pipe compound or Teflon tape as described above.