Abstract: To provide for positive sanitary separation of water spilling or overflowing from a washing sink unit (1), a cleaning sink unit (2) and a third water receiving unit (3), which may be formed as a sink unit or as a drain board, the second unit, located between the first and the third, is surrounded by a raised zone which merges with a forward region of a water retention rim (4) surrounding all the sink units, the raised region (5) terminating short of the rear edge region (19) of the sink unit, and leaving with the water retention rim (4) adjacent the rear edge region a gap (7). A drain and overflow opening (8) is located in the gap. Surfaces of the sink which may be essentially planar are pitched towards the overflow and drain opening, so that any water splashing or overflowing from any one of the three units or regions (1, 2, 3) will drain off into the overflow without flowing back into another one of the units or regions.