The first part of our DSSP is the Site Utilities page.  On this you have the property, the building, the water and sewer entering the building from the street, storage vessels, and connection details.  All of this is scaled and marked with elevations such as TOP 1124.7  and INV 1123.19.  There is a lot of engineering notes, fairly jargony, related to weeping tile, manholes, dimensions and slopes.

The idea here is the water is contained, and channeled, and flows in the right direction to leave the property.  The mechanical room is shown and how deep the water and sewer lines are, shutoffs, crossing and the valve at the end that regulates flow downstream.