A filter assembly for filtering a wash fluid to be circulated by a circulation pump in a dishwasher appliance includes a filter member, housing, discharge chamber, and relief valve. The filter member defines a discharge opening, and includes an outer wall. The housing at least partially surrounds the filter member, and may include a peripheral wall. The housing defines an aperture that extends through the peripheral wall. The discharge chamber is defined between the outer wall and the peripheral wall. The relief valve includes a valve body surrounding the aperture on the peripheral wall, and a valve member disposed within a cavity defined by the valve body. The valve member is movable between a first position in which fluid communication between the discharge chamber and the cavity is restricted, and a second position in which fluid communication between the discharge chamber and the cavity is permitted.