We usually locate the roof drains near the low point

We were working on the layout of the roof plan for a large, irregularly shaped building, designed with the structure gently warped to shed water to the edges. A drafter was adding roof drains to the plan, and I noticed that he was locating some of the drains about half way up the slope between the low point and the high elevation. I asked him why he was doing that, and he replied that he thought the drains at mid-slope would collect half the runoff on its way to the low point.

"Oh, I forgot to tell you," I said. "We usually locate the roof drains near the low point." He looked skeptical until I added, "It's office policy."