A filter device (10) includes a filter element (12) in a filter housing (14) with fluid connection points (16, 18) for the non-filtrate and filtrate. Fluid can be passed through the filter element in both directions for filtrating the non-filtrate or for backwashing for cleaning particle contaminations (72). A pressure control (36) generates a post-suctioning effect to improve the cleaning of the particle contaminations (72). The filter device (10) is designed as a one filter-element solution. In a predetermined exchange, the single filter element (12) for filtering can be used for backwashing or can be backwashed using the pressure control device (36). A hydraulic system (64) and a method for backwashing a filter element (12) of a filter device (10) is provided.