When the refrigerator runs its automatic defrost cycle, this frost melts into water. That water needs to go somewhere. It drips down into a small pan located at the bottom of the freezer floor, enters a small hole, and travels down a tube (the drain line) to a drip pan situated near the compressor at the very bottom of the fridge. The heat from the compressor eventually evaporates this water into the air.

Once you have access to the drain hole, check for visible debris. Use a Q-tip or your finger to clear the opening.

Periodically slide out the bottom kickplate to check the drain pan for mold or standing water.