We should differentiate between data center and compute center in this discussion. Compute is the source of energy consumption and thermal dissipation scale we are discussing.
The deal needs to be something like pay to build the water and power capacity for your load, but the regional utility operator gets to build the facilities which they will own and operate. You buy power and water from the local utility under the existing rate structure.
They're already using almost 10% of the available water for the region. Water isn't infinite and I would imagine using it will leave pollutants behind.
Taxpayers are already paying helping to pay for the electricity to run these data or compute centers.