Ebbtide, My rule of thumb is 1 gallon of water per person per day for drinking and food prep. Sanitation and first aid are extra allocations.
Your family of four for two weeks at one gallon per person per day equals 56 gallons of water. Call it a 55 gallon drum's worth. If there's kids involved, I'd add some extra. They don't understand why they can't drink as much as they'd like or as they always have before.
Realistically, I'd be looking at keeping four or five (maybe more) of those 55 gallon drums on hand if you're serious about your water supply handling all needs (cleaning of bodies, clothes, dishes, house/environment). Rationing becomes important.
As to how/where to store the water, anywhere it fits. Like in the garage, garden or tool shed, basement, ..... anywhere it's cool and out of sight.
Here are links to water storage info:
http://waltonfeed.com/self/water.html
http://www.emprep.com/water_storage.html
http://ianrpubs.unl.edu/foods/g1536.htm
http://www.annapolis.gov/public_news.asp?ID=6769 (very basic, as are most govt websites)
http://www.nationalterroralert.com/readyguide/safewater.htm (Homeland Security site)
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(rave mode on)
Unfortunately, Katrina won't induce any more preparedness in the American populace than did 9/11/01 World Trade Center attack, Hurricane Andrew, or any other previous natural or man-made disaster/emergency. There have been plenty of "wake-up calls" given already and, as so many of the folks on the Gulf Coast show, they chose to do no preparation for possible hard times. I call it the "ostrich syndrome" because these folks keep their heads obstinately stuck in the sand, being unwilling to acknowledge that when TSHTF it could land in their neighborhood.
Or, more dangerously, they choose to believe the the government will take care of them (as if the govt gives a s**t about their family) when the deal goes down. It's more dangerous because it lulls them into believing there's going to magically be a safety net under the tightrope we all walk daily (it's called LIFE and it has inherent & intrinsic dangers to it, recognize that fact and deal with it). IMHO it's up to us to recognize that when the deal goes down we will each be individually responsible for taking care of ourself and our family.
As in previous disasters, the efficiency and ability of American individuals and organizations to render aid to each other far outstrips the behemoth staggering of the govt's aid mechanisms. We need to remember the value of government to take care of BIG issues like highways, utilities, airports, and other infrastructure elements. That's macro management. But aid is rendered one person at a time, which is micro-action. In my experience, this level of performance is better managed and rendered by individuals and small groups than by the (typically bloated) departments, bureaus, and agencies of government.
The illustrative example to me was the executive of a water bottling company who had semi-loads of water headed into the affected area within hours. However, when he called local authorities to inform them of the incoming water, he was told that the trucks wouldn't be allowed in until the locals gave the go-ahead. Here was a man used to making pressure-cookker decisions that affect the many people who work for him, to say nothing of the very life of his company and by extension himself & his family, being stonewalled by some local yokel having trouble dealing with the fact that all the s**t had hit the fan.
Or I can turn on the local Seattle area news any night of the week to see warehouses being filled, emptied into planes/trucks for delivery to the Gulf Coast, then being refilled again by the working stiffs, school classes, office workgroups, soccer moms, elderly who remember the Depression's hard times, and the myriad others who make up the fabric of the American populace.
Uncle Sam is taking care of himself. I intend to do the same.
(rave mode off, thanks for the bandwidth)