The most common reason water accumulates in the bottom of a refrigerator is a problem with the appliance's defrost system. Automatic defrost systems use a timer and heater to melt frost from the evaporator coil. When the melted frost drips off the coil, it should drain neatly into a tube that carries it to a pan beneath the unit. When the drain is clogged or the tube is obstructed, the water backs up in the freezer and overflows to the compartment below. That situation can result in standing water under the produce drawers. Removing the defrost drain's or drain tube's blockage ends the standing water issue.
Defrost Overflow Solution
Clearing the defrost drain or drain tube necessitates figuring out whether the problem is ice or other debris blocking the drain or something stuck inside the tube. If it is just ice over the drain, then a little hot water to inundate the drain for a few seconds probably will clear the drain. Clearing the tube, though, may require combining hot water and baking soda in a turkey baster and forcing the solution down the drain to remove ice particles or other debris. Either way, a homeowner can repair the problem himself in many cases. Removing the panel that covers the evaporator may be necessary in order to locate the actual drain.
Door Frame Heaters
The standing water problem may have relate to condensation caused by high humidity in the refrigerator. Modern appliances are designed to be as energy-efficient as possible, and many refrigerators have an energy-saver switch. It is basically a control switch to turn on the door frame heaters that dry the humidity that often causes condensation. Turning on the energy-saver feature disables the heaters and saves electricity, but the refrigerator's interior may sweat as a result, and the condensation can run down and pool in the bottom of the appliance. A test can determine whether or not the energy-saver feature is the standing water's cause. It requires turning off the energy-saver feature for one day to enable the heaters, removing the standing water and seeing whether or not the water returns.
The refrigerator’s freezer compartment keeps perishables such as meat and vegetables very cold for long-term storage, and items such as ice cream require the extreme cold to remain solid. If a refrigerator has cooling issues, the ice crystals that form on those items or their packaging may thaw and drip onto the compartment floor. The situation also could cause dripping into the fresh food area below and result in standing water or a pool of another substance, such as melted ice cream. Cooling issues may be caused by dirty condenser coils on the back of the refrigerator, a frosted cooling coil or even a compressor malfunction, which may require replacement.
Water Dispenser Supply Lines
If the refrigerator has a water dispenser, its supply lines may not be connected well or could be damaged. Even a tiny leak in that system can cause major water pooling inside the unit. If shutting off the supply of water to the refrigerator stops the standing water problem, then the supply lines probably are the source of the situation.