The invention relates to an incremental advancing unit that can be hydraulically actuated by pressure changes, for a water distributor. The incremental advancing unit allows the advance over several angle increments (IW) and thus skipping non-active outlets (A5, A6) of the water distributor. Outlets (A3 to A6) can be reversibly marked active or inactive by the user by setting means (H3 to H6). The different step widths are predetermined by a reversibly settable strike (D1 to D5) of a piston (KO) of the incremental advancing unit.
