Gazork, I agree, water is and can be the key difference, I am very fortunate to be located in a rural area. I do have my own well and septic.
My shallow well is down 21 feet and my deep well 65 feet, water for me is very simple, old time wind mill or hand pitcher pump or hand pump jack, No electric needed!
I plan on having a shallow well in my safe room/ root cellar, with a little hand pump. The cylinder that pumps the water is down below in the water and every time you stoke the pump handle you move a metal rod inside a cylinder with leather cups that pulls the water up the pipe, ( not well casing ) to the hand pump. Very simplistic old time design and still works fine today. Yes it has its draw backs, but in a time of no power, you will always have drinking and wash water.
Not saying it can't happen, but it would be pretty tough to contaminate that ground water. It would take some catastrophic activity to stir the ground formation up and make it unsafe to drink. Then there would be all kinds of filters etc. after that to keep it safe to drink.
I have hand dug shallow wells for years and always enjoyed playing with them and the free water they can produce.