A clogged dishwasher is a messy headache, but you can usually fix it without a professional. Most drainage issues stem from trapped food, grease, or a simple mechanical oversight.
Always clear your sink disposal before starting a dishwasher cycle.
It is usually on the floor of the dishwasher, near the base of the lower spray arm.
Pour a kettle of hot (not boiling) water into the bottom to flush the line. Step 5: Check the Drain Hose
If you have done all of the above and there is still standing water, try a chemical-free flush.