A control system for a sump pump driven by an AC motor includes an AC power line having an input adapted for connection to an AC power source and an output adapted for connection to the AC drive motor. A controller is connected to a controllable switch in the AC power line, to control the opening and closing of that switch. Redundant float switches are coupled to the controller and adapted to be mounted in a sump to supply the controller with a signals when the liquid in the sump rises to a selected level. A timer in, or coupled to, the controller alters the control signal to open the controllable switch if the liquid level in the sump remains above the selected level for a preselected time period.