Water has it all, except for the existence of futures contracts, as far as I can tell. Once you see a market for water futures forming, bend over. That's when the manipulation will begin. Crooks prefer manipulating financial markets over building reservoirs.
The plausible explanation for the worldwide shortage is that the population is growing faster than the supply of clean water. Add global warming to the mix and you have plausible explanations for worldwide droughts. That's the cover story. It's true enough to mask the artificial shortages that will be caused by the speculators and hedge funds.
So how can you invest and make money in water now, before the bubble tops?