Get matched with top dishwasher installation pros in Phelan, CA

Yes, a dishwasher needs an air gap to prevent backflow. Additionally, in many locations, air gaps or another measure to prevent backflow are required for building code compliance. There are alternatives to an air gap, like a Studor vent or a loop and trap design, but an air gap is the simplest and most popular solution.  

No, you do not need a garbage disposal to have a dishwasher. A dishwasher will work without one, and while it's rare to see a home with a dishwasher that doesn't have a disposal, it is possible. The two appliances pair well and are often installed together because a disposal simplifies meal cleanup.

However, your dishwasher should not be used as a replacement for a garbage disposal. Subjecting it to continuous food leftovers can lead to major clogs. If you choose not to install a garbage disposal, you should thoroughly rinse your plates or scrape excess food into the trash or a compost pile before loading them into the dishwasher to prevent plumbing issues.

To create a siphon break and remove any chance of dirty sink water or water that backs up into the sink from getting into your dishwasher, your dishwasher drain hose needs to have a high loop or an air gap device as part of its installation. All building codes require at least a high loop. In many places, it’s necessary to install an air gap device to meet the code.

If the dishwasher is in working condition, start and run a complete cycle with nothing inside. Let it drain and sit overnight before removing the hoses. In theory, it should effectively drain. You may find residual water in the hoses, but you can plug them. If the dishwasher breaks down midcycle it can sometimes be full of water. You’ll need to manually remove the water with a plastic cup before removing the dishwasher.