So we'll move the datacenters from the tiny town to just outside of a giant city which will probably move that percentage down to only a few percent if even that. Problem solved!

You're looking at the wrong metrics to compare here if we're trying to just gauge how efficient a datacenter is or is not. This metric could be useful if the datacenters are attached to the municipal water system and thus begin to be a massive load compared to what was originally planned/built, but in terms of understanding the total water use compared to other industrial users its kind of a meaningless statistic.