A filter device may include a ring filter element arranged in a filter housing in an upright manner. The ring filter element may have an upper end disc, a lower end disc, a filter material arranged therebetween, and a dirt pot provided on the lower end disc. The dirt pot may have a water separator arranged therein and provided on the lower end disc, a protruding pin, and an opening on a base side of the dirt pot. The filter device may include a functional element having a channel configured to receive the protruding pin. A portion of the functional element may be configured to penetrate the opening of the dirt pot such that the ring filter element is sealed at the opening. The portion of the functional element may have at least one water discharge opening. The filter device may be operational when the pin engages into the channel.