I got sucked into running the numbers on that "delete emails to save water" thing. Best estimates I can find are that live datacentre storage in the UK has a median water usage of ~80ml/GB/year. So a terabyte of cloud storage consumes 80 litres a year.
Network losses from leaks are on the order of 10-15,000 litres per person per year.
Glad we can see the culprit is definitely old forwarded cat photos.