Not all water is potable water, but only potable water is used for cooling at Dalles.
> "I fail to see how this affects the overall water supply in Oregon"
"[ Google Data Center, The Dalles Oregon]
Google has negotiated an agreement with The Dalles that would substantially boost the water available through The Dalles Public Works – and, in turn, the volume of water available to cool Google’s enormous server farms. Google would pay the $28.5 million cost of the upgrade to the city’s water treatment and storage facilities under the agreement. In addition, Google has negotiated a new package of tax breaks that would exempt its data centers from much of the property taxes that other businesses pay.
The Dalles Mayor Richard Mays said the new deal would require Google to pay about $57 million in property taxes and fees over two decades for the first of the new data centers, and approximately $66 million more over 20 years if it builds a second data center.
That would be a substantial boost in revenue for the historic community in the Columbia River Gorge, but the deal would continue excusing Google from much of its property tax bill.
But some residents and city officials are skeptical of the new deals, too, partly because details were negotiated behind closed doors and some details of the agreement remain oddly secret. The Dalles won’t say, for example, how much of the expanded water supply it expects Google will consume. This is concerning to members of the community.
Google is paying for the expansion, handing over some of its water rights, and will pay the same rates as other industrial customers for the water it uses. Since 2008, Google has awarded over $2 million in grants that impact Wasco County and more than $10 million in grants to Oregon nonprofits and schools. In the long run, the expanded Google data centers will provide The Dalles community with more water, additional jobs, and lots more Cloud Storage for your Aunt Edith’s cat photos. Scrutiny remains, but such is the nature of progress."
City of The Dalles is right on the large Columbia River. However, the towns drinking water does not come from the Columbia River ...
"The drinking water for the City of The Dalles is supplied by three groundwater wells and two surface water intakes located on South Fork Mill Creek and Dog River. The Dalles' public water system serves approximately 11,350 citizens."
So I could see a potential worry about a minor water source being drawn beyond it's capacity, especially in case of persistent drought. (I don't think "lost from the environment" addresses the problem).
I wonder if google could instead use water directly from the Columbia River for cooling?