"net positive water" [...] by tricks such as collecting rainwater
A typical techno-behemoth greenwash. Collecting rainwater merely tags as 'yours' for the PR value water that would return to the aquifers naturally anyway. Very reminiscent of suppliers of "green electricity", which amounts to no more than entering into contracts with a proportion (often quite small) of their generation sources. I investigated this a while back and asked whether they had a member of staff sitting there painting the electrons green as they passed. They didn't see the joke.