Shower Head Dripping After Turning Off Water
Place a soda straw in a glass of water and cover the top of the straw with your finger, then lift the straw upward. You will notice that the straw stays full as long as you keep your finger on the top of the straw. Fundamentally, the same thing occurs in a shower arm. When the water is turned off at the mixer the riser and the arm are full of water, and the line is closed off at the mixer. The water in the arm will remain in place by surface tension until air works its way up the pipe, releasing the water. In some instances that may occur immediately, which gives the illusion of water running after the valve is turned off. In other instances the water may remain for hours before it finally releases. This is especially true of shower heads that have a small flow restrictor orifice. This is simply a fact of nature and no cause for alarm.