Our project is a dormitory building attempting LEED certification for major renovation. The building is located inside a university campus. I would like to know if the approach the design team is considering meets the requirements of this credit.
The project will collect rainwater to be used for flushing the toilets, we have calculated the 95th and 98th percentile events based on more than 10 years rainfall events data (95th percentile: 49.55mm and 98th percentile: 65mm). The runoff volume required to be managed has been calculated via the Small Storm Hydrology Method Runoff for the roof and the all pavement areas (For the 95th percentile: 61.39 cubic meters and 80.54 cubic meters for the 98th percentile). In order to comply with the requirements, the rain water collected will be stored in a main rainwater cistern for the entire campus, located outside the LEED boundary of the project and 3 cisterns of 10 cubic meters each shall be located on the roof of the project, connected to the main rainwater cistern of the campus in order to receive the water for flushing the toilets.
My question is the following: by proving that the main cistern is big enough to store the runoff volume from either the 95th or 98th percentile storm event, and that it is directly connected to the cisterns located on the roof of the building, can we comply with this credit?