In LEED BD+C: New Construction V4.1, the outdoor water use reduction credit (2 points) states that alternative water sources can be used to achieve an additional 30% reduction. However, unlike in the V4 version, there is no V4.1 Outdoor water use calculator tool that will help us calculate the total percentage of water reduction.
In the case of the project I am working on, we are only using grey water to irrigate the outdoor vegetation. However I am unsure how to calculate the water percentage reduction from baseline, is there a tool available that will help me calculate that percentage?
I would also like to ask you if we have an outdoor pool, should we consider it in this credit? And if yes, how do we include it in the calculations?

Thank you in advance for your reply!