Turn off the dishwasher and unplug it or switch off the circuit breaker
Shut off the water supply to the dishwasher
Remove the bottom rack
Check the drain filter and remove any food debris
Bail out standing water with a cup or use a sponge or towel
Remove the drain hose from the sink drain or garbage disposal if needed
Place a bucket under the hose and let the water drain out
Inspect the air gap, drain hose, and garbage disposal for clogs
Clean the drain pump area if accessible
Reassemble the hose and parts securely
Restore power and water
Run a short rinse cycle to confirm the dishwasher drains properly