My friend lives in an area where city water fails when electric power fails
(at least it has in the past).

What are the options available for single family homes to provide "off the
grid" water for a few days at least for a family of 3 or 4? I assume that
you'd need some tanks and bypass valves and a battery operated pump. Anyone
know how much that might cost.

Any leads or ideas would be appreciated. I'll be Googling on several
factors, especially the hazards of bio-nasties growing in large tanks of
water. I'm assuming these tanks would be on line and thus constantly have
the water changing just like a standard water heater.

TIA,

--
Bobby G.