One of the cheapest ways to store larger amounts of water is by using water bags rather than drums. An even cheaper way - if you have the space - is several plastic garbage cans with lids. A thirty five gallon can at Home Depot is about 20 bucks in my neighborhood. Just remember to tip them over and replace the water every six months or so. Also advisable is a good filter like a Berkey to remove any odd tastes picked up from storing in the plastic cans.
To do: Identify dangerous plastics that will contaminate water (plastic should be avoided as a long term container and if it will be exposed to heat) some transparent plastics can serve to purify water if left in the sun but again it may be a trade off in terms of long term problems.
To do: Verify and make this content useful if possible "You did add 5-7 drops, about 1/8 teaspoon, of chlorine bleach per gallon of water stored? If not, empty them and refill, add the bleach ($1.00 to purify about 1,000 gallons). It will store for six months before you need to do this again. Remember, according to the Chlorox folks, bleach will begin to lose potency at the rate of about 20% per year after six months. Adjust your dosage accordingly, or make sure you are using fresh bleach in the first place. Better yet, buy calcium hypochlorite and make your own water purification solution - dissolve one heaping teaspoon of powder in two gallons of water to make your bleach solution. The powder itself will keep indefinitely. Mix this solution at the rate of 1 to 100 - about a pint per 12.5 gallons - to disinfect water."
