Roaches can live in hostile environments, without food or water, for long periods of time. Even the cleanest homes can become infested with roaches, and they will commonly claim the kitchen, notably the dishwasher, as their home base. Most people are unsure of how to eliminate roaches without contaminating their dishwashers with toxic poisons. You can eliminate roaches through non-toxic means, however, and they will stay gone for good if further preventive measures are taken.
Sanitise the Dishwasher
Pull any dishes out of the dishwasher and set them aside. Then remove the bottom rack from your dishwasher and examine the drain. Roaches love tight spaces --- especially if that tight space comes with food and water. Remove any food debris from your drain. Place 1 cup of white vinegar on the top rack, and run your dishwasher on the hottest cycle available. Roaches cannot stand extreme heat or cold and this will flush out any stragglers and sanitise your dishwasher at the same time.
Eliminate Entry Points
Once you have sanitised the dishwasher and flushed out any remaining roaches, you will need to make sure they cannot make a home out of the appliance again. Check the bottom of the dishwasher for open spaces or cracks and fill them with caulk. Apply a fine layer of boric acid around the vicinity of the dishwasher and around any plumbing built into the exterior walls. The layer of boric acid should be nearly invisible to the eye, according to Mike Potter, an entomologist with the University of Kentucky.
Remove Remaining Roaches
Kill any remaining roaches by mixing one part boric acid, two parts cocoa and two parts flour and sprinkling the mix around troublesome areas of the kitchen, such as the floorboards, plumbing and the refrigerator. In order to keep roaches out of your newly sanitised dishwasher, you have to be sure that there are none left in the rest of your kitchen.
Take Preventative Measures
Keep roaches out of your dishwasher by always leaving the door locked shut, especially when there are dirty dishes waiting to be cleaned. Never leave food out on the kitchen counters and take the trash out daily. Clean the drain of your dishwasher at least once every two weeks to be sure no food is left lying. Sanitise your dishwasher every other week, or as needed.