You're right, I can't see drain pipes anywhere! Not only are they not visible, but the roof looks like it's flat. That would mean that they need the drainage system even more. My husband and I are looking to get a new drainage system installed on our house. We would love it to be concealed this well. It's certainly much more visually appealing. http://www.northshoreroofinganddrains.com/drainage-vancouver-drainagesurveys-drain-installations-repairs.htm