Abstract: A modular water filter assembly is disclosed. The modular water filter assembly includes a primary module having primary filter media for treating water; a secondary module having a first end and a second end; and a manifold defining an inlet connectable to a water source, and an outlet connectable to a water dispenser. The secondary module is removably coupled to the manifold at the first end thereof, and to the primary module at the second end thereof, the secondary module defining a flow path for carrying water therethrough. The water filter assembly is variably configurable for treating water passed from the water source through the inlet of the manifold and through at least one of the primary module and the secondary module and then through the outlet of the manifold. An appliance incorporating such a modular water filter assembly is also disclosed.