Here in Phoenix, water is definately life. I am planning on a minimum requirement of 2.5 gallons per person per day for summer days. That might not be enough... that's just my first guess.

So, I need to have water stored so I can survive if city services are out. But, being lazy (I don't want to rotate stocks) and forgetful (I won't remember to, anyhow), I need a survival water supply that I won't have to worry about until I need it.

What about getting one or two water heaters and hooking them, without electricity, in series with my home's cold water supply? The water would rotate itself just from using water in the house. I would add bypass/isolation valves so I could remove a tank from the circuit for repairs or when the city supply failed. I'd plan to use a short potable water hose hooked to a water heater drain to extract water for emergency use. I would add enough water purification goodies to my supplies so that I could treat all the stored water if it was questionable (say, if contaminated city water made its way into the tanks before I isolated them).

Question 1: At around $250 for 50 gallons, this is expensive. Are there any cheaper solutions for inline, pressurized water storage?

Question 2: Could my stored water drain back into the city's lines if the city supply lost pressure? Should I add a check valve to the system to prevent that?

Question 3: What alternatives to this crazy scheme would work well even though I am lazy and forgetful?