Some dishwashers run fine, but will have problems with the water used during the cleaning, either refusing to drain it or leaking it out onto the floor. If the dishwasher refuses to drain, this may be a sign that the drain is clogged. Open the dishwasher and check that the drain is not obstructed. If the machine leaks, try to locate the source of the leak. If it comes out the front of the machine, it may mean there is a problem with the seal; if it comes out the bottom, it may indicate a leak in a hose or a pump. If it leaks bubbles, you may simply be using a detergent that is too sudsy.