Diagnosis
That’s almost always a clogged defrost drain. When the fridge auto-defrosts, the water is supposed to go down a tube in the back and into a pan to evaporate. If that tube is blocked, it overflows into the fridge compartment.
How to Fix It
You’ll need to clear the drain tube. 1) Unplug the fridge for safety. 2) Remove all the food and the crisper drawers. 3) Look at the back wall of the fridge compartment. At the bottom, you’ll see a small drain hole. There’s usually a little plastic cover over it. Remove that cover. 4) Use a turkey baster or a long pipe cleaner to gently push into the hole and clear any gunk (food particles, mold). 5) Mix a cup of warm water with a tablespoon of baking soda and slowly pour it down the drain to flush it. You should hear it draining into the pan below. Wipe everything dry, plug it back in, and you’re set.
If That Didn't Work
If water keeps pooling, the drain tube might be frozen where it goes through the freezer wall. This happens if the freezer is set too cold. Try setting the freezer a few degrees warmer (aim for 0°F) for a couple of days to let that ice plug melt. You can also use a hairdryer on low heat, aimed at the drain hole area from the inside for a few minutes to carefully thaw it.
Heads Up
To prevent this, avoid putting loose, wet produce directly on the shelves. Use the crisper drawers for fruits and veggies, and make sure nothing is blocking that back wall where cold air circulates.