Why is water backing up in the dishwasher when it is not in use?

Water backing up in the dishwasher when it is not in use may be due to a clog in the drain hose or a problem with the dishwasher's drain pump. This can prevent water from properly draining out of the dishwasher, causing it to back up. It is important to address this issue promptly to prevent further damage to the dishwasher and potential water damage to the surrounding area.