Abstract: Water is supplied from a mains water supply station to a main supply conduit which feeds a plurality of regional supply networks, via respective pressure reducing valves, at respective regional pressures. Each regional supply network has a boundary value for a parameter related to a property of the water, which may be water pressure or concentration of a water treatment agent. Each network has a critical point at which the value of the parameter is deemed least acceptable. Water supply characteristics in respect of each regional supply network are monitored and the water supplied into the main supply conduit is processed to ensure acceptable values of the parameter are maintained at each critical point.

Abstract: A pilot valve (2) for controlling operation of a hydraulically-actuated pressure reducing valve, the pilot valve including a housing (4), and a first valve member (15) mounted in the housing for longitudinal movement along an axis relative to the housing and to a second valve member (22) in response to the outlet pressure of the pressure reducing valve. The first valve member is provided with an aperture (20) and the second valve member comprises a closure portion which varies the effective flow cross section of the aperture in accordance with relative longitudinal movement between the first and second valve members. An adjuster (26) controls the relative rotational position of the first and second valve members, the closure portion having a profile such that relative rotation between the first and second valve members causes the closure portion to vary the effective flow cross section of the aperture (20).