Not sure there is an answer. Ours leakes as well, but it appears to be a missing part (the black washer-type seal that fits below the hot water dispenser). Even when properly assembled It has always leaked. I think it's simply a really bad design. I just went to Hoover.com and no parts are available for this model, so I think we're going to be forced to buy a new one.
Jim
September 2007