Get a free diagnosis before you call a repair pro or buy parts.
Most often it's a clogged dishwasher filter or food trap, a blocked or kinked drain hose, a clogged air gap, or — if the dishwasher was recently installed with a garbage disposal — a disposal knockout plug that was never removed. A failed drain pump is possible but less common.
On most models the filter twists out of the floor of the tub. Remove the bottom rack, twist the filter assembly counter-clockwise, rinse it under running water, and reseat it. If drainage doesn't improve, the blockage is likely further down the line.
Usually yes — the majority of drain problems are clogs you can clear without parts. A diagnosis first tells you whether you're looking at a simple clean-out, a modest part like a drain pump, or something that justifies a pro.