Using granular calcium hypochlorite (swimming pool shock) to disinfect water is a two step process.
1. To make a stock of chlorine solution (DO NOT DRINK THIS!) dissolve 1 heaping teaspoon (about one-quarter of an ounce) of high-test (78%) granular calcium hypochlorite for each two gallons (eight liters) of water.
2. To disinfect water add one part of the chlorine solution to 100 parts water to be treated. (That’s about 4 Teaspoons full per gallon of water)
3. Let the mixture sit (with the top off) for at least 24 hours before drinking(I have other directions that say 1 hour)
Be sure to obtain the dry granular calcium hypochlorite since once it is made into a liquid solution it will begin to degrade and eventually become useless as a disinfecting agent. This also means you should make your treated drinking water in small batches, for example enough for a few weeks at a time at most.
Another plus for using calcium hypochlorite to disinfect water for emergency use is that a little goes a very long way. A 1-pound bag of calcium hypochlorite in granular form typically costs only a few $US dollars and can be obtained in any swimming pool supply section of your hardware store or online. This amount will treat up to 10,000 gallons of drinking water, which is enough for a family of four for some six or seven years at a gallon per day per person!
Calcium hypochlorite will store for a long period of time and remain effective as a chemical drinking water treatment. So get rid of the household bleach and buy a can of Calcium hypochlorite for your disaster emergency water disinfection needs. It lasts far longer and treats far more water than the traditional chlorine bleach water disinfection treatment.
A good water filter should filter out the chlorine or calcium hypochlorite before you drink it. You can test your water supply with a simple pool chlorine test kit and that will tell you how much chlorine you have in your water.
I know this seems like a lot on water, but good clean SAFE water is the basis of life and with out it you will die. Nothing could be worse than drinking water from a stream, lake or river (untreated and un-filtered) and getting a bug that will give you the runs and eventually kill you and you will die a miserable slow death from water born disease. With no hope of any kind of treatment from a doctor or medications that may help combat these deadly diseases. This is why water treatment and water filtration is vitally important.