Signs

• If your dishwasher is backing up, you’ll first notice the problems when you find water sitting in the bottom of the unit after your run a load of dishes. If you are lucky, the water will be sudsy and clean smelling. Sometimes the water has food particles floating in it and smells bad. Even after the water eventually drains out, you can still smell the bad odor just inside the dishwasher. The smell will stop you from using it, rendering the unit useless.
  
  

Causes

• Your dishwasher usually backs up because of a clog in the drainpipe. When the dishwasher drains after a cleaning cycle, it sends a large amount of water into the pipe. When there's a blockage, the water hits the barrier and, with nowhere to go, ends up back up into your dishwasher. The water contains food debris as well as pipe muck from the clog. Bacteria feed on this debris, giving the water a foul smell.
  
  

Solutions

• Getting rid of the blockage in the drainpipe will stop your dishwasher from backing up. If you don’t have a garbage disposal in your kitchen sink, trying pouring ¼ cup of baking soda into the drain. Wait five minutes, then pour in 1 cup of vinegar. This combination of ingredients will foam in the pipe, dislodging parts of the clog. They’ll also deodorize the pipe. If that doesn’t work, try using a commercial drain opener. If you do have a garbage disposal, contact a plumbing professional to fix the clog. Using a drain opener could damage the disposal.
  
  

Considerations

• If your dishwasher still smells bad after you clear the clog and water is no longer backing up into the unit, wipe out the interior with paper towels soaked in vinegar. This removes any lingering food particles. Next, fill a dishwasher-safe plastic cup with vinegar and place it right-side up on the dishwasher’s top rack. Run a load; the vinegar will deodorize the interior of the unit as well as the tubing that leads to the drainpipe.