Dishwashers generally overflow due to a leak in the system o using the wrong kind of soap when loading the dishes. Either situation can lead to a kitchen floor full of water.
Putting the wrong kind of soap in the dishwasher might sound silly, but it happens occasionally. Even a little dish soap in the unit in addition to the normal soap can lead to a layer of foam that ends up pushing through the seals around the door. The end result is a wet, soapy floor. If the user accidentally puts some dish soap in the dishwasher, it helps to add a bit of vinegar before starting the machine to cut the foam.
Vertically mounted dishwashers can end up with a leaky tub seal at the bottom, which sends water under the dishwasher and in front of the unit. It is fairly simple to take the seal off its housing and put a new one in to resolve the problem. Motors that have horizontal mounting are tougher for the do-it-yourself homeowner to deal with.
If the dishwasher's water supply tube develops a leak, water ends up on the floor without even making it to the dishwasher. After pulling out the dishwasher and checking the seals, this is the next troubleshooting step.