The most common reason your rain shower head is leaking is that it's clogged with mineral deposits. The deposits prevent some water from coming out when you have the shower running, and the leftover water can drip out when it's not in use. To fix this, simply clean your shower head. Leaks can also be caused by worn washers, so when you take your showerhead down to clean it, make sure the rest of your hardware is in good shape.