Q: My brother-in-law says our dishwasher should be installed with an “anti-syphon loop.” What is he talking about?
A: An anti-syphon loop is made in a dishwasher drain line to prevent any backflow of water between the kitchen sink and dishwasher (or vice-versa). A simple method to accomplish this is to make a big loop with the excess length of flexible drain hose. The hose should loop up just beneath the countertop and then back down to the garbage disposal or main sink drain to prevent back-siphoning. Another method is to run the drain hose from the dishwasher to an antisiphon valve, which you can find at your local plumbing supply store or home center.