Abstract: A regulating valve such as especially a water tap or mixing valve, having an inlet passage and an outlet passage and a valve passage located therebetween, the cross sectional area of said valve passage being adjustable by means of movable valve actuation member, the valve passage being shaped as an elongated slot in the wall of the inlet passage, extending generally in the axial direction of the passage, and the slot being formed between opposed edges which are operatively connected with the valve actuation member so as to be mutually substantially parallelly displaceable towards and away from each other, whereby the valve can be made as a low noise valve with small space requirements. The invention provides for a mixing valve in which the individual valves for cold and hot water, respectively, can be located in a common elastomeric member very close to each other and even mounted in a narrow cartridge held in a valve housing in an easily replaceable manner.