Water!!

It's been written often enough - without water we're screwed in days. Without food - weeks? The bigger and heftier we are the worse it gets with thirst and the better, by degrees, with food. All things being equal I'd like plenty of both thanks.

With that in mind - water. One prepping boos suggest, rightly so, that ANY clean container, including old soda pop bottles - once cleaned, will do. True. But obviously we want as much stored as is reasonable along with the means to collect rain water, have a well and or sterilise it.

Now in an ideal scenario we'd have our own well or water source (stream, river or what-have-you). Most survival refuge selling sites (survivalrealty.com being the main one) have a measure of how many gallons per minute said well or water source can and does provide. Ditto your central heating system - they use the same measure. 

Make sure you have means of storing water (I'd suggest two large tanks), collecting water (a water butt from down pipe off of your roof) and filters and chemicals to clean and sterilise water with. Water boilers included. Of the images I've added my preference is for the 2nd tank as it's easy to use a pallet truck with and thus moveable.

Of the filters I'd prefer the kind where, as your water source comes in, it does it's job. Equally and you might prefer such a set up, the kind where you store your water as is and filter it when you need it is ok. But it is a slower way of being ready than a drip-feed system. Look also at sterilizing solutions and tablets.

Some products and containers can and do leave a taste. Better to be moaning about how the water tastes than be thirsty eh?

Water butts are, for how they might save your life - or at the very least water your crops, wash clothing or property (as opposed to be used for drinking if you have a better source  - cheap as chips. The kind were all surplus water spills over is spot on. A 210-gallon version is a tad over 30 bucks.

Consider using 2nd hand versions of the above if they have been professionally cleaned and are intact and good to go.