Abstract: The present invention relates to fluid control and management, particularly to valves and regulators for controlling the flow of a liquid, such as water. We described an isolating valve assembly comprising a first isolating valve demountably fluidly couplable to a second isolating valve. The first isolating valve comprises a first valve body and the second isolating valve comprises a second valve body demountably attachable to the first valve body. The first and second valve bodies each includes a respective valve comprising a valve plug and a valve seat against which the valve plug bears to prevent flow of fluid through the valve body when the first valve body and second valve body are in disconnected configuration. At least one of the valve plugs includes an axial actuator stem arranged such that, when the second valve body is attached to the first valve body, the axial actuator stem bears against the other valve plug to cause both valves to open.