Water collects inside refrig at the bottom

You did not say what kind of unit you have: side-by-side, freezer on top, or bottom freezer. Anyway, you will have to remove the cover to the freezer after unplugging unit. Then wash out drain pan with hot, soapy water, and blow out with hose nozzle. Then pull out from wall and remove rear cover so you can clean the coils, condenser fan blades, and drain pan with spray soap and a hose nozzle. Wash out well and use a wet-vac to get water up. When I have a hand truck handy I would always unload the unit and take it outside and wash it all out from top to bottom with bleach and water. It's the best way to get it like new again. Probably, the drain is gunked up with food and dirt. I usually find peas or something like that in the drains. Clean it all out well because a dirty unit will burn up the compressor quickly. You should do this at least once a year and every six months if you have a dog or a cat in the house. Here are some manuals: https://dl.dropboxusercontent.com/u/...zer_refrig.pdf
https://dl.dropboxusercontent.com/u/...ile_Artica.pdf
https://dl.dropboxusercontent.com/u/...ide_refrig.pdf
https://dl.dropboxusercontent.com/u/...e%20Manual.pdf

It could be your defrost drain line is clogged.

How to Unclog a Defrost Drain | eHow

http://www.ehow.com/how_7956121_fix-...in-system.html