I have a well.  I have a 200 gallon open top tank.  
What i want to do is consider options for keeping this tank full at all times (or once a day if there is no more cenrtal power..).  The things that I am conserned with include maintaining pressure, the energy required to fill the tank, keeping the water potable (as free from as many contaminants as possible), and keeping it under roof (I dont want it outside).

I had originally thought that I would keep it in the attic.  I figgure that minor construction can support the weight of this tank and the 2000 lbs or so of water.  The force of gravity can keep the sinks, toilets, and showers running.  BUT, if I loose power, what systems shall I consider to provide the necessary energy to pump the water from the well to the tank?

Any thoughts that you have, please chime in...

If your planning on putting in the time and money to install this water system, might as well spend a little more and get yourself a generator and wire it into your house, or atleast wire it to your water system. This way even if you lose power, you can just go out and start up the gen once a day for a little while and power your pump to fill the tank.
EZ

I agree-The time and effort you would put into design,construction,and maintenence of a one off system is going to be way more than grabbing an off the shelf generator that would also provide a better lifestyle if the power grid goes down. A one off system =nothing in resale and the generator can always be sold off as part of the property or by itself

Open-top?!? Ever seen what color water turns when a mouse drowns in it?

This is a cheap solution for keeping it full