What Are Plumbing Riser Diagrams?

A plumber riser diagram is not necessarily drawn to scale, but it must be accurate enough to clearly show the concept. It is often created as a 2D diagram rather than an isometric 3D or an even more complicated axiomatic drawing.

What it needs to show is how the risers and various other pipes relate to one another and to fixtures, drains, traps, and valves or taps, but with just a series of lines. Water and waste pipes are shown as solid lines while vents are shown as dotted lines.