A filter assembly for filtering water from an external source, the filter assembly including a manifold assembly mountable to an appliance and being in fluid communication with the external source and a cartridge assembly, the cartridge assembly being replaceably fluidly couplable to the manifold assembly, the filter assembly includes a first and a second fluid tube, the first fluid tube being fluidly couplable to the external source being an unfiltered fluid inlet, the second fluid tube being a filtered fluid outlet, the first and the second fluid tubes each having a barbed end for coupling to the manifold assembly. A tube retainer assembly is associated with each of the first and second fluid tubes, the tube retainer assemblies each having a port being fixedly couplable to the manifold assembly, the port having a retainer bore defined therein for receiving a tube barbed end therein, a retainer ring disposable on the tube, the retainer ring compressively engaging a barbed surface of the tube barbed end and being fixedly bondable to the port for forming a fluid tight seal between the fluid tube and the retainer assembly. A cartridge assembly and a method of disengaging the cartridge assembly from a manifold assembly are also included.