Hi! I just got back a review on this PR and the reviewer made 2 comments:

1- ET0 values seem off to the reviewer, they are accurate and from local goverment agencies, I can prove that. Same for precipitation values. I know they may seem strange for a reviewer from the Northen Hemisphere, I am in the south and our season are opposite to what a reviewer might be familiar with, could that be a factor? (i.e.: the month with highest demand is January). Also, the site is located in a tempered-humid climate, which means there is not much water demand if the plant material is chosen wisely. Usually water demand can be met with just rainfall with hardy species. 

2 - The second comment I got was that the calculator gave a 101% savings. This is an intensive green roof, only a small portion of it is irrigated and the rain water harvest is more than the actual water need. So it means we have a surplus water, where I believe the mix-up might come from. 
Any ideas on how to get around this? I can not change what the calculator gives, and I have no way to enter a value for the harvested water  we are giving. I can't understand what I am doing wrong to get a 101% value in water savings.