That doesn't seem right. As far as I know, rivers/lakes/aquifers are pretty much the definition of fresh water.

Yes they are the definition of fresh water, not purified water.

Running fresh water is relatively clean, but it doesn't mean there isn't giardia or other microbes / impurities.

Okay, but Intel promised to return more freshwater than it used. So it can't simply take freshwater, purify it, and return it at a surplus.

Maricopa and Pinal counties have lots of agricultural water that either comes directly off the Colorado river via canal, or is pumped from shallow alfalfa field runoff groundwater that is too full of nitrates to be even remotely potable.

We also, unlike the CA Central Valley or the Midwest who are apparently cool with depleting their resources as fast as humanly possible, are acutely aware of our groundwater supply constraints, given that we live in a desert, and practice a lot of aquifer recharge and management.

Intel cleans it, uses it, and dumps it into aquifer recharge, which cleans it even further.

The midwest gets more than enough water via rain, so nobody worries about water. Farmers don't irrigate crops, they just accept lower profits in drought years. You might be thinking of the west where water is a problem.

I'm pressing 'X' to doubt, right now:

https://www.climate.gov/news-features/featured-images/nation...

edit: Maybe I should have said Great Plains, which overlaps, but is not precisely the same as, the Midwest.

The great plains does have issues. The rest of the midwest doesn't.