Turn off power to the dishwasher
Shut off the water supply
Remove the bottom rack
Take out the filter and clean it
Remove standing water from the tub
Check the drain hose for kinks or clogs
Disconnect the drain hose and clear any blockage
Inspect and clean the air gap, if present
Check the garbage disposal inlet for blockage
Clean the drain pump and impeller area
Reassemble all parts securely
Run a short rinse cycle to test drainage
Call a professional if the clog remains