DO NOT use Liquid-Plumr or any type of caustic drain cleaner product in a clogged dishwasher.

It's normal that the bottom of the tub is filled with water during operation a couple inches deep or so ... how much water depends on the design, brand/model, etc.

All dishwashers have some sort of overfill protection, usually a float. The normal fill level is timed. Some units may leak a little if the overfill level is reached, particularly if the cycle is paused and restarted.

All dishwashers have a pump to spray water over the dishes for washing/rinsing, and to drain the water. Some designs use one pump for drain and recirculation with a reversing motor. Others have two pumps/motors, each one dedicated to either recirculation or drain.

Seems unlikely that "crud" would accumulate from non-use. Dishwashers should be used regularly, however. Some residual (clean, from the last rinse) water is left in the pump to keep the seals moist. If left unused long enough, it can evaporate, allowing the seals to dry-out.

I had the same problem a few weeks ago where the water never fully pumped out. I removed the hose at the sink tie in and blew in it. It would bubble out so I put together and tried again. It would pump some water to drain then slow right down, not fully pumping out the bottom.

The culpret: I found a small bottle cap seal, slipped through the strainer on the bottom of the dishwasher and would cover the drain hole to the pump like a check valve.

dadoes: Thanks! Where is the float located? Is it hard to access? How do I access it? If I wiggle the float and it starts pumping out the waste water, I know I found the culprit.

zl700 - blow out the line: good idea but how?

Thanks to all!

The float is there to keep it from overfilling, not to activate the drain pump. There may be a 'cancel' function on your DW that will cause it to start the drain cycle.

You may need to put a large pan underneath and detach the drain hose and let it drain into the pan. You could also detach the hose at the other end and attempt the same thing.

As weedmeister says, the overflow float usually does not trigger the machine to drain if an overfill occurs, it simply overrides the timer (assuming that perhaps the overflow occurred because the timer got stuck during the fill period) and shuts off the water valve to prevent further filling. Usually the float can be seen at the front left (or sometimes right) corner inside the tub.

Stating the brand and model of your dishwasher would help a lot in offering advice ...