If your dishwasher is Leaking check the following
Dishwasher Not Leveled
This is a very common reason for a leaking dishwasher especially if this was a new installation. The framing in a dishwasher is made up of mostly thin sheet metal, so if it is not sitting flat and level things can get distorted very easily. Watch the video on leveling your dishwasher.
This is not very common in most dishwashers. To check this look for rips and distortion of the seal. If it is ripped or distorted you will need to replace.
This is a more common place for a leak to develop. This is easy to check, remove the front panel and carefully inspect around the seal for water dripping or stainage. If any is found replace the dispenser gasket.
Water Inlet Valve
Usually it is the connection to the water inlet valve that ends up leaking. Check this connection ( there is usually some sort of adaptor between the valve and supply hose) for leaks. Check the connection on the back of the water inlet valve also. Ocassionaly a water inlet valve will leak around the solenoid in this case replace the water inlet valve.
Drain / Circulating Pump
Some dishwashers have separate drain and circulating pumps. Some use one pump to serve both purposes. In either case you will need to check the housings for leaks along with all the connections. Some dishwashers have a seal that leaks down into the pump . This is easy and inexpensive to replace. Follow the tutorial on replacing the pump.
The door latch can become loose or misalinged. Check both the striker and the latch. To adjust the latch you will need to remove the front panel and adjust switch until properly aligned.
They can cause problems, but this usually only happens from opening a heavy load of dishes on the door. Occassionaly a broken spring or cable occurs. You will need to remove the toe kick and maybe the front panel to inspect.