The Schaich drains an area of 38.1 km², which lies entirely within the Schönbuch natural area. Its highest point is the flat, 582.6 m high summit of the Bromberg south of the Hengstbrunnen, over which the southern watershed runs to the large catchment area of the Goldersbach and its tributaries, which drains over the Ammer to the Neckar. Further east, in the south, the catchment area of the Reichenbach, which flows into the Neckar at Pliezhausen, is bordered by the Reichenbach, then on this side by the continuously shorter Neckar tributaries.