Per her website (which is hosting the transcript of the interview here: https://ocasio-cortez.house.gov/media/press-releases/ocasio-...) seems that the cause is known and acknowledge to be construction

"""

...A few weeks ago, while Congress was in recess, I visited Morgan County, Georgia, where Meta is building a massive data center campus. They are clear cutting forests and began heavy construction, including explosive blasting, and families in the area are starting to see not only their water pressure decrease, to your point about water availability, but their appliances have all stopped working because it is decimating their water quality.

They now rely on bottled water to drink and prepare meals, and nearby residents' water bills are expected to increase by 33%. In fact, I have a jar right here. This is the current drinking water in Morgan County, Georgia, right after a data center was constructed, the Meta data center was constructed. ...

"""

I wonder why they're using up and dumping all the water then. If the water was clean they'd consume none... it'd just flow through their CPU's, into tanks, and back into municipal water supply.