We don't have a shortage of water we can drink, we have the potential for drinking water shortages in the future assuming that only demand continues to grow. We don't even really have industrial and agricultural shortages anywhere either, not in the developed world at least - we have areas where we're utilizing a high percentage of available water and where water use is regulated for large consumers and areas where ground water tables are being diminished which is the only real problem.

The other key thing to remember is that water supply is incredibly geographic, the Arizona River basin for example is a common example of a water system in danger which is why someone placing a facility that uses a lot of water is unlikely to build there if they're doing a non location specific thing like running a date center. You'd be far more likely to put it somewhere like Virginia near the Potomac where there's no shortage at all or in germany and Ireland where again they have huge amounts of water. (I use these examples because it's where aws data centers are)

If I don't flush my toilet then it's not going to help the watertable in Capetown or Arizona, but if an Arizonian telephones me and says 'I want to do some math but my calculator uses too much water' then I can do that math for him using the huge amount of water endlessly falling from the sky here and that will save water in Arizona.

According to the UN development program the most common form of water scarcity is economic, largely due to the complexity of infrastructure projects - the chicken and egg braindrain problem where no one that has the education to build and run such systems wants to live in such difficult areas. The internet is already moving towards improving this. Remote learning is allowing people to study to a worldclass level without needing to physically have that infrastructure locally, ai improves this hugely as it can explain things in people's first language and as it's abilities continue to grow this will only continue. Likewise automation of construction and monitoring allows high efficiency and environmentally sustainable facilities to be established so water availability and quality can be improved thus reducing the global water scarcity.

Also in developed nations reduced cost of infrastructure makes it ever easier to create more water efficient systems especially with active monitoring of agricultural crops and targeted water supply, etc. And as you rightly point out places with limited supply can always just build a desalination plant, they're getting cheaper all the time and the ones currently in operation are working really well, Isreal and Jordan for example working together to refil the sea of Galilee (a fresh water lake that was declining due to over use).

These stories have no substance, they exist because ai is trending news story and everyone loves to find reasons to bad mouth anything new. Yes, It's a valid concern that must be taken into consideration but an article is junk if it doesn't start by explaining using water in areas with huge amounts of it isn't even slightly a problem and that this is of course standard operating procedure when locating data centers.