Your refrigerator drip pan sits underneath the appliance. A thin sheet of plastic or metal with upturned edges, it sits on the floor behind the grate at the base of your refrigerator. The drip pan protects your floor from water. When your freezer defrosts, the melted water is directed down to the pan. The small amount of water evaporates and disappears. When the drip pan leaks, you end up with water on your floor.
A few drops of water on your floor rarely causes a problem. If your refrigerator drip pan reguarly leaks, it could damage the floor. Water that reaches your walls can soak the baseboards or drywall. Over time, this opens the door to mold growth in your wall where it can go on to spread throughout your home. In addition to filling the room with a foul musty odor, mold can also trigger health problems in your family members.
Pull the grate on the bottom of your refrigerator up or off, then reach under the unit and pull the drip pan out from under it. Rinse it free of dust and debris, and make a visual search for a crack or hole. If you can't find a flaw in the pan, try filling it with water and look for water escaping. Don't try to repair a broken pan; the chance of it cracking again are too great. Instead, purchase a new one at an appliance repair or supply store.
Refrigerator drip pans are rarely the cause of water leaking out from under the appliance. More common culpurits are leaking water supply lines or melt water tubes. If you can't find a hole in your drip pan, check out the rubber tubing in your fridge. If you find mold growing on an undamaged pan, wipe it clean with a sponge soaked in white vinegar. This will kill the mold and its spores and deodorize the pan.