Underground water supplies are located in confined and...

Underground water supplies are located in confined and unconfined aquifers, these can of course be alongside oil. The underground water supply that we do use is not associated with oil in anyway. Geologist explicitly go out of their way to not disturb surrounding aquifers in the extraction of oil. The useable aquifers occur in between metamorphosed sedimentological strata much like oil, however, are a distinctly separate to oil deposits. Since we don't use a polluted version of either.

In saying the above, fracturing sediment structures is done in a way that it does not disturb surrounding aquifers, oil companies do not want polluted oil, and the governments do not want polluted water. So, the two are barely associated with one another. Unless by an unforeseen mistake.

Oil deposits required pressurised carbon life forms to reduce the C from general bio-waste products, to coal, all the way to oil. So, after briefly outlining what we are dealing with, I compose a final question.

Would you drink underground water that is associated with oil? No, right? Hence, why fracking oil reserves does not have any effect on useable aquifers.

...Geology 101...