An upright water extraction cleaning machine having an assembly of tanks efficiently stored on and interconnected to the machine is shown. The tank assembly has at least two tanks nested with one another and having one-way valve mechanisms on the bottom thereof. The two tanks are slidably mounted to one another and the tank assembly is slidably mounted and operatively connected to the machine. With this structure, the user can quickly and easily remove and refill the tanks and continue operation of the machine with a minimum amount of interruption and delay.