Waste line on the surface?

[jjonas (Jeffrey Jonas)]

Drain pipe depth

I know that sewer and drain pipes must be protected from freezing & damage but is there a minimum depth that drain pipes must be buried? I cannot find reference to anything in the IRC and I do not have a UPC available. Here is a photo of an efficiency apartment sewer line from an inspection yesterday. [Underwood Pickfair photos 058.jpg]