Abstract: Apparatus for controlling the flow of water through a pipe including a valve and an orifice plate and supplying a water distribution system comprises a governor actuating a pilot valve in a servo system controlling the valve. The governor has two diaphragms linked by a tension spring the extension of which is determined by the rate of flow through the orifice plate. The first diaphragm operates a valve member of the pilot valve and is subjected to the differential pressure caused by flow through the orifice plate. The second diaphragm is loaded by a compression spring and its displacement is dependent upon the control pressure at a tapping in the pipe. The movement of the valve member is the combination of the displacements of the two diaphragms, and raises the control pressure at tapping when demand for water increases.