For the Whirlpool ET22DK, pull the fridge out and look at the back. Look for the black rubber plug about halfway between the top and bottom of the unit, in the center, with a plastic tube going down to the bottom of the unit. That's the drain line. You can disconnect it from the black rubber plug, and check the drain line to make sure it is unobstructed. If it is blocked, replace it.
Also, every 3 months or so, pull the drip tray out from under the unit. To do that, pull the black grill off the front (located under the refrigerator comparment door). On the left, about 6 or 8 inches in, there's a plastic tray. Lift up a bit, and pull toward you. Clean it, and reinstall it. Chances are you will also have a lot of dust built up under the unit, especially on the cooling coils. Use a vacuum cleaner to get as much of the dust out as you can. A little maintenance once or twice a year will help to keep your refrigerator running right for many years.
NeverMind, December 2005