Lets take a hypothetical where next week, all utilities across america are sold to private hands and the monopoly privilege was abolished(if only such a thing could happen!). Would the utilites that operate the water supply be operated in the same way as deer park, clear springs, and other water bottle companies? Anytime that you go into a grocery store, there is always bottled water available but yet under government hands, there are shortages. I would assume that prices would stay the same or go down based on supply and demand.
How can we convince average voters that privatizing all utilities will be better than the government monopolies we face right now?
Make them read :)
http://www.vforvoluntary.com/wiki/TheMythOfNaturalMonopoly
But seriously, I would probably point out the theory behind why there's no such thing natural monopoly and then show them that historically there was competition in utilities before the government monopolized them and after doing so, prices tended to rise.