To paint a picture of what I am doing: I am installing a trench drain in an open bay that is attached to a catch basin. It will have a recycling system to reuse/clean the runoff. The pipe exiting the catch basin runs into the room that will contain this rec. system( about 10' away). The problem I have is that my plumber ran the line exiting the catch basin on top of the foundation pad and when we pour concrete it will be very difficult to repair if there is ever a problem. Should he have buried this pipe below grade? What are the implecations of him not doing so? Would it be necessary to run the pipe like he did in order to maintain the proper slope? If so. Why couldn't he use a thrust block? I had the rep from the trech drain supplier look at it and he said it was fine, but I don't necessarily agree. I just want someone's knowledgeable opinion that can lead me to some more information about this application.