Two words

[waif69]

Swimming pool. Most of our water storage is kept in our swimming pool. I figure that for most scenarios, this would work fine for us as it provides more than 7k gallons and can be purified as required if the zombies were to attack.

[Cowboy]

I like a bit more control over my water storage. A swimming pool can be exposed to elements that could make in unusable. It is also harder to protect if the zombies attack. These work well:

http://www.etanks.com/products/details.aspx?productid=1828

[waif69]

good tip, I look to do that with the next house. I just have to hope that the zombies don't come before we move.