Abstract: Fluid leaks can be detected and controlled in a pressurized piping system. Apparatus for this includes control logic; in communication with the logic, a flow detector and/or a pressure detector, and a control valve. One or more of the following is or are provided also: the flow and pressure detectors are both present, and both as single units; the control logic, the flow and/or pressure detector(s) and the control valve are in close proximity to one another; and the control valve has a baseline condition of being shut off. A remote control device can remotely interact with the control logic. Pressure decay and/or flow properties can be employed. The fluid can be water as, for example, in a residential, commercial or institutional system.