A set of building components of a mechanically secured block building system for constructing structures include a plurality of trough blocks. Each trough block has an interior cavity characterized by a U-shaped cross section and a pair of oppositely disposed inner ledges recessed relative to top surfaces of opposing outer walls. A bottom of each trough block includes a plurality of apertures therethrough. In an assembled configuration of the trough blocks, the trough blocks are mechanically secured in an end-to-end arrangement and the interior cavities align to define a continuous pipe channel therethrough.