Dishwashing appliances and methods, as provided herein, may include features or steps such as activating the drain pump for an activation period and receiving a pump-status signal during the activation period. Dishwashing appliances and methods may further include features or steps for detecting a pressure (P1) upstream from the drain pump during the activation period, determining a condition at the filter based on the pump-status signal and P1, and directing the drain pump based on the determined condition.