It may not be practical to store water for a year. At a minimum it would be 365 gallons of water per person per year, the equivalent of about eight 55 gallon drums. The more you store the better, but I have another method that will help you purify water if have a water supply, but not purified. This is not to replace water storage, but to provide another method to help provide safe drinking water. One pound of dry chlorine will provide enough drinking water for a family for a year.
You will need:
Medicine dropper that measures in milliliters and teaspoons. (This is needed when you need to purify water with liquid Clorox bleach. You can purify water with this method
1 qt container that measures in ounces and milliliters. (Mark with black marker the 16 oz./1pt)
2 gallon container
15 gallon container
Pool chemical testing strips (measures free chlorine, alkalinity and ph).
1 pound of Dry Chlorine 70% calcium hypochlorite, 30% inert ingredients
Add and dissolve one heaping teaspoon of high-test granular calcium hypochlorite (approximately ¼ ounce) for each two gallons of water. The mixture will produce a stock chlorine solution. DO NOT DRINK THIS.
To disinfect water, add the stock chlorine solution in the ratio of one part of stock chlorine solution to each 100 parts of water to be treated. This is roughly equal to adding 1 pint (16 ounces) of stock chlorine to each 12.5 gallons of water (approximately ½ liter to 50 liters of water) to be disinfected. To remove any objectionable chlorine odor, aerate the disinfected water by pouring it back and forth from one clean container to another.
Dry chlorine must contain only Calcium Hypochorite about 70% and the other part inert ingredients of about 30%. It must NOT contain anything else. Anything else is poison. I found a good source for this chemical through Kayak Kataloge Corp of Lancaster, NY (800-526-7337). Order item number CB235220 +/- 4.00 per pound. Called SUPER Shock Chlorinator -1lb.
Once the final water has been mixed together, allow it to sit for 30 min. With the testing strips, take a sample and follow the directions to test the water.
If it smells of too much chlorine, here is another secret, if you grind up a vitamin C tablet and sprinkle it over the water. Allow another 30 minutes to pass and the excess chlorine will fall to the bottom of the water as harmless salt. The water is safe to drink. It is still recommended to run the water through a water filter.
It is a good idea to practice this before you need to know as well as exercise caution.