A modular slotted drain assembly having a slotted drainpipe, one or more base drain members positioned in communication with the slot of the drainpipe, and one or more reducer drain members stacked atop the base drain members. The reducer drain members have non-parallel upper and lower edges, such that one end of a reducer drain member is taller than its other end. An assembly is created such that the slope of the upper edges of the reducer drain members is not parallel to the drainpipe axis, allowing the upper edges of the reducer drain members to correspond to the slope of the ground surface.