Abstract: The disclosed technology includes a tank system including a gravity tank configured to contain water at atmospheric pressure, a rigid pressurized tank positioned within the gravity tank and configured to contain water at a pressure greater than atmospheric pressure, and a piston assembly positioned below the rigid pressurized tank and configured to open and close the rigid pressurized tank. The gravity tank is configured to channel water at atmospheric pressure into a toilet bowl at a first velocity and the rigid pressurized tank is configured to channel water at the pressure greater than atmospheric pressure into the toilet bowl at a second velocity. The second velocity is greater than the first velocity.