12-24-2013, 09:04 AM
If I understand your question correctly (?) is it ok to drink water that ran off a concrete coated roof. I would think so. A lot of municipal water tanks are made out of concrete, as are hundreds of miles of concrete conduits that feed the tanks. Water spends very little time in contact with a concrete roof. The storage tank material is much more important than the surface used to catch the water. In Alaska most catchment tanks are under ground (where the water doesn't freeze), made of concrete, and integrated into the concrete foundation, and I've never heard of anybody getting sick drinking from them.