<p>The pivotable positioning lever (11) serves for the adjustment of at least the throughflow amount and with it the water valve can be changed over from a cut-off position selectively to one of two different user units. An operating member (2) is provided with a stop (3) releasable by the user. The stop allows pivoting from the cut-off position to a non-prioritized user only after a release movement of the stop. The releasable stop with a shaft (30) parallel to the positioning lever is displaceably located in the operating member in a guide, on which a radially projecting stop body (31) is formed. The stop is pressed into a position by a spring (32) in which the stop in the cut-off position locates on an inner ring-shaped cover surface (120) on a hollow ball-shaped housing part, whilst a release of the stop occurs by being pushed inwards against the force of the spring in the housing part (12).</p>
