A drinking container includes a main reservoir; a filling reservoir; a filter connecting the filling reservoir to the main reservoir; a plunger assembly having a plunger head in the filling reservoir and a shaft extending therefrom. The shaft defines a passageway from to an opening in the plunger head, to allow addition of liquid through the passageway into the filling reservoir. A valve allows closing of the opening to allow the plunger head to be urged into the filing reservoir, thereby urging liquid in the filling reservoir through the filter into the drinking reservoir.