Answer: Neither. The dishwasher's drain is simply a rubber or flexible plastic hose running from a diverter valve under the unit to your sink drain or disposal and is easily accessible inside the cabinet under the sink. I would first check to see if that drain hose is attached to the cabinet as high as possible. This is to prevent backflow of drain water once it has passed that point in the drain line. If the hose is not attached into a high loop try doing that and see if the problem persists. Some installations use a "air gap" mounted into the countertop (visible from above) for this purpose. The smallest point in the D/W's drain route is where it connects to the drain/disposal. If it is actually partially blocked, it is most likely right there.