I have a Whirlpool Thin Twin stacked washer/dryer, recently I noticed standing water underneath the washer.

1.I check the hose connections and all seem dry.
2. I fill the tub with water and let it sit for a few hours, the water level never changed.
3. I took the front panel off and checked for water leaking, but could not immediately see anything.

After reading a few sites, I think it is the pump that is leaking. But cannot locate it or confirm it is the problem. Any advice?

I found different source for a leak on my unit. There was an overflow of the drain pipe that only happens after most of the water drains from the washer. The delay was due to the plug being down the pipe.