Your dishwasher works by spraying your dirty dishes with a stream of water. This dirty water is then pumped out of the dishwasher and into your home's sewer system through a drain hose. These drain hoses are built of tough materials, but are still prone to kinks in the line, which eventually lead to leaks. There are some stopgap fixes available to fix a leaking dishwasher hose, such as repair tape, but it's not that much more difficult, or expensive, to just replace the entire hose. This will result in a more permanent fix for a leaking dishwasher hose.
Turn off the power to the dishwasher. Either unplug it or turn off the power to the electric circuit where it is installed.
Position yourself underneath the sink where the drain hose for the dishwasher terminates. Depending on your installation, the drain hose could be connected to either the garbage disposal or the sink trap. Unscrew the drain clamp with the screwdriver. Pull off the end of the drain hose.
Make a note of where the middle portion of the hose is connected. Most municipalities require a drain loop in the middle of the hose. This is done by raising the hose a set amount of inches from the ground. The middle part of the hose needs to be higher than the inlet on the sink/disposal and the outlet on the washer. Consult your dishwasher installation directions for more details.
Follow the drainhose to where it is connected to the dishwasher. Disconnect the drainhose from the back of the dishwasher. If this is hard to reach, you will have to disconnect the dishwasher from it's mounting brackets so you can reach the hose connection. Be careful if you have to do this because the dishwasher is still connected by the electric wires and water supply.
Connect the end of the new drain hose to the back of the dishwasher. Secure with the hose clamp.
Run the hose to the termination point underneath the sink. Secure with the other clamp.
Run the dishwasher on an empty load. Check for leaks. Tighten any clamps if necessary.
Some municipalities require that a dishwasher be installed by a certified professional. Check with your city or county building permit section for details. The above steps are just a guideline. Always follow the instructions given by your manufacturer.