This past weekend I purchased a Little Giant submersable utility pump on sale at Leslie's for $87.00. Before I would do as H823Putt and use a few garden hoses(4 to be exact) and just syphon the water out. It really wasn't that bad and only took a little over an hour but it always left a few inches in the footwell. Now it takes just 20 minutes and one hose and only leaves an 1/8'' of water.
I had a hard time convincing myself to buy one as it seemed like a waste of money but that all changed after I used it for the first time.
I've never even opened my drain valve, so I don't know how long that would take. But from what I've seen others post, it takes waaay to long and yes, even if it's on the floor.