Line the area around the Bosch dishwasher with towels to absorb any water which leaks out.
Open the dishwasher and remove the bottom dish rack. This can be done by pulling the rack straight out from the dishwasher.
Scoop any water from the Bosch dishwasher with a cup and dump it into the sink. It is normal for there to be one cup's worth of water in the dishwasher at any given time, and it will be removed during the next wash cycle.
Rotate the drain filter latch counterclockwise until the filter can be pulled up and away from the Bosch dishwasher.
Scrub the filter in soapy water using a scrub brush to remove any build up or blockage.
Rinse any leftover soap from the filter with clean water.
Insert the filter back into its cradle in the Bosch dishwasher, then turn the filter latch clockwise to lock it into place.