Going to the comments from the article-

a poster called "gary"

""A better option than storing bleach is storing calcium hypochlorite, which when combined with water, will make bleach. 1 lb. of this is will purify 10,000 gallons of water and will cost you about $10 plus shipping on Ebay. It will, for all intents and purposes, store for an indefinite period. It is highly caustic, so it has to be stored properly, but at least you won’t have to worry about getting rid of it after 6 months. Calcium hypochlorite is also known as “pool shock”, so you can often find it at pool supply stores, but look carefully, because most of the pool shock I’ve seen has other additives you don’t want in your drinking water.""

I picked up 16 ounces from target for 1.98 at end of pool season.
As one teaspoon will make 2 gallons "stock Chlorine solution"

that should cover me for a decade

reference link http://water.epa.gov/drink/emerprep/emergencydisinfection.cfm looking under "choose a disinfection method