A system for autonomously cleaning a floor has a robot having a chassis. A clean water tank and a dirty water tank are disposed within the chassis. A valve in fluid communication with the dirty water tank receives dirty water from a cleaning surface during a cleaning operation. A docking station has a platform. A docking station drain communicates with the valve for receiving contents of the dirty water tank when the robot is in the docking station. A water source communicates with the clean water tank to fill the clean water tank when the robot is in the docking station. A charging structure charges the robot when the robot is in the docking station.