Oil companies are pumping this crap into aquifers. I had no idea they were allowed to do this. No wonder people's wells become polluted if they live too close to one of these fracking sites.California officials have ordered an emergency shut-down of 11 oil and gas waste injection sites and a review more than 100 others in the state’s drought-wracked Central Valley out of fear that companies may have been pumping fracking fluids and other toxic waste into drinking water aquifers there.
CA halts injection of fracking waste, warning it may be contaminating aquifers
I would be worried if I relied on one of these aquifers for drinking water.