In every water cooling loop for consumer grade computing hardware, the water is cycled through for hundreds (thousands?) of hours before servicing is needed. I think it would be pretty easy for a company with such massive resources to have some sort of small on site water treatment facility or filtration system. Swimming pools filter their water, why can’t data centers?

I don’t think the water would be potable after running through that sort of hardware because the piping is probably not safe for transporting drinking water, especially at high temperatures when different chemicals could leech into the water. There’s also fittings, lubricants, anti-microbial additives, etc. that would further complicate things.