A refrigerator appliance includes a cabinet, a first side support, a second side support, a first adapter plate, a second adapter plate, and a water tank. The cabinet defines an internal cavity. The first and second side supports are disposed within the internal cavity, define a drawer receptacle therebetween, and have first and second laterally inward facing surfaces defining first and second longitudinally extending slots, respectively. The first and second longitudinally extending slots are configured to receive drawer rollers. The first and second adapter plates are secured to the first and second laterally inward facing surfaces, respectively, and have third and fourth laterally inward facing surfaces defining third and fourth longitudinally extending slots, respectively. The water tank is disposed within the drawer receptacle and slidably engages the third and fourth longitudinally extending slots such that the water tank is adjustable in a longitudinal direction.