I have no data on hand to ...

I have no data on hand to answer questions 1 and 2 but definitely my suggestions on question # 3.

First of of all you should educate the students about the importance of water and what they must do conserve it. I have observed that people leave water faucet running while brushing teeth. Persuade students to shut-off faucets (Water taps) while brushing teeth. Another way to limit the water usage in the toilets is to use sensor controlled faucets.

Facility maintenance team should be instructed to repair the leaks the moment they spot it.

If there is a landscape area at the facility, automatic irrigation system with latest smart controllers should be used. Garden hose should never be used  to irrigate grass and other planting material.

I hope you like my suggestions and make sure that these are implemented at campus in question.