These will be called water credits within LEED and they are very easy to get. We see many buildings that use low-flow plumbing fixtures, and they also collect rain water for toilet flushing, for storage in cisterns for irrigation, for all kinds of uses.
So that again is something in the building code that is very difficult to do. Depending on which province you are in, that rain water that you collect and water that comes out of your shower, and even water that comes out of your toilet, is all defined the same way and treated the same way.
As an example, there's rain water that is stored and then used in toilet flushing, where there is really no human contact. Just over the last few years, architects and engineers were able to incorporate it into buildings and get it by the municipal plumbing inspectors.
But this is one of the challenges. You have something that is freely available, that makes a lot of sense—not to use treated water to flush your toilet—and it's actually not as easy to implement on the building scale as we would think.