Not unique in many parts of the country. Here in central Illinois it is common to drill a water well and have methane along with the water. The phenomenon is probably related to coal deposits, so likely any state that has such deposits overlaid with aquifers will see methane in the water. We have a few fortunate locations that have no need for the commercial product, but some variability in others necessitates a propane or commercial NG backup. For the lady in Colorado, she merely needs to keep her faucets closed. That works fine here.
Joe