Disconnect the Waterpik shower head from your shower. Wipe off any excess water.
Remove the tip from the Waterpik shower head. Detach the water reservoir from the main part of the Waterpik.
Squeeze the main part of the Waterpik body and the reservoir cap at the same time to squeeze out the blue part. Pry around the swivel cap with a flat head screwdriver to loosen and remove the cap.
Unscrew the two screws at the bottom of the main Waterpik body. Slide the interior of the Waterpik shower head out through the opening.