My mom's refrigerator drips water inside. Is it because she is opening it too often, holding the door open, or is there another possible reason? At times it's so bad there are pools of water. She lives in Missouri where it has been extremely hot and humid.
Warm moist air goes into the fridge and condenses. This is where you get the moisture. Normally, there's a drain, perhaps below the veggie drawers, that ducts the excess moisture away to a tray below the evaporator coils.
It's common to have this drain clog. You can try pouring in boiling water to clear it, but you may overflow the bottom tray and need a mop.
You can also try soft copper wire, like 14 gauge stripped electrical wire, which should not poke any holes in anything yet still be stiff enough to clear the jam.
Most refrigerators manufactured today receive their actual "coolness" from the attached freezer. The attached freezer sections must have periodic defrosts, otherwise the air pathways which circulate the cooled air will become blocked.
In the good old days, the consumer freezers were defrosted manually when they became so full of frost that nothing much would fit. The newer ones all have auto defrost at varying periods from daily to thrice daily.
The vapor pressure of water in the presence of a freezer is very high - an open freezer or refrigerator will literally suck the moisture out of the air (this is why your lips crack while you are skiing and why the glass cooler doors at the store are difficult to open immediately after you close it) and condense it to water or ice.
Anyway, the defrost cycle produces lots of melted water, which must drain somewhere; which is usually underneath your appliance or the floor. There is usually a tube to drain the freezer water from defrost to the drain pan. What usually happens is that mold grows in the drain tube. Someone else mentioned above to use a soft wire to clean the tube, this is correct procedure to clear the blockage.
To cure it for a long period (roughly equivalent to the elapsed time between the purchase of the refrigerator and now) run bleach down the tube to kill the mold (yes it's probably mold) growing in the tube. What I usually do (or have done) is pinch off the low end of the tube and fill it with household bleach and leave it for a bit (5 minutes is fine). Then open it and allow it to drain and rinse well with water. Clumps should come out, uck!
Oh yeah, don't forget to empty the container you use catch all the junk that comes out of the tube.
Hope this helps.