You can repair minor damage to a dishwasher drain hose with tape designed to handle moisture but it’s probably better to simply replace it. Dishwasher hoses are inexpensive items that, although they require some muscle to change, are best swapped out. You don’t want to find your kitchen has flooded because of a faulty part that usually costs between $10 and $30.

Leaks, poor drainage, failure to start, water not heating, and excessive noise frequently require service.

A clogged air gap can cause a dishwasher not to drain. There are, however, other potential issues that can lead to improper drainage. For example, if you have attached the air gap to a garbage disposal and forgotten to remove the knockout plug, wastewater may backflow into the dishwasher. Check that the air gap is installed properly, and then look for clogs in the air gap and dishwasher filters. 

Some signs that your dishwasher is going out include:

• The door no longer latches 

• Dishes are still dirty after a cycle 

• Dishes are cold after a cycle 

• Rust inside or outside the unit 

• Cracks inside the dishwasher tub

• Water collecting at the bottom or outside the unit

If your dishwasher is not energy-efficient or is older than 10 years, you should also consider replacing it. Repairing an older model may be more expensive than replacing it with something newer and more energy- or water-efficient.