Abstract: A reservoir of a water filtration system carries a projection such as a fin on its outer surface. The reservoir is removably received in a housing, such as a pitcher, such that the projection engages a shelf in the housing. A passage in the reservoir can have a nonuniform taper that corresponds to the outer surface of a water filtration cartridge. A grippable member such as an indicator dial can be movably attached to the outer surface of the housing. For each orientation, use indicia on the grippable member align with use indicia on the outer surface of the housing in a unique visual configuration. A water filter cartridge for the filtration system can have an inner surface that extends between a water inlet and a water outlet. One portion of the inner surface starts at the water inlet and joins at its other end to a second portion of the inner surface. The second portion of the inner surface is about as long as the first portion, and is tapered.