Indoor water handlers are a crucial component in the overall functioning of your air conditioning system. They perform double duty, removing both heat and moisture from the air at once. There’s a small pan at the bottom of the handler, which catches moisture as it drips. At the other end of the pan is a drain line. Sometimes debris can clog the drain line, which causes the pan to plug and pool over. Fortunately, this problem comes with an easy fix. You can remove the drain line and clean it with bleach or vinegar water until the build-up clears.