Letter Re: Disinfecting Your Drinking Water


I have noticed over the years that when I read about water purification during bad times that Calcium Hypochlorite is mentioned as the way to go for storage and use. Typically, it is suggested to buy an abundance of the material so one can be charitable and pass out small plastic bags of the chemical with instructions for its use to purify water. I’ve never before seen simple and concise instructions that ANYONE could understand for treating drinking water with Calcium Hypochlorite.

Using what I’ve gleaned from the Internet, with numerous revisions, I believe I have the information that one would need to properly use the Calcium Hypochlorite for water purification all here. “Calcium Hypochlorite” is one of the best chemical disinfectants for water, much better than household bleach. It destroys a variety of disease-causing organisms, including bacteria, yeast, fungus, spores, and viruses and is much more stable than liquid chlorine.

How to Disinfect Water Using “Calcium Hypochlorite”

Using granular Calcium Hypochlorite to disinfect water is a two-step process. “Mix only in a Plastic or Glass container, NOT METAL!!”

  • To make a stock of liquid chlorine solution: dissolve 1 heaping teaspoon (about one-quarter of an ounce) of high-test (70%) granular calcium hypochlorite for each two gallons (eight liters) of water. (This liquid mixture is the stock that you will use to treat your drinking water.)
  • To disinfect water, add one part of the liquid chlorine solution to 100 parts water to be treated; stir thoroughly with clean wooden or plastic spoon until hypochlorite crystals dissolve.
  • Example: 6 oz of liquid solution treats about 4.75 gallons of water in a five gallon bucket. (4.75 gal = 608 oz. of water)
  • Let the mixture sit at least 30 minutes or more before use.

Be sure to ration 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 disinfectant. This means you should make your liquid chlorine solution in small batches, enough for just a few weeks at a time.

An advantage of using calcium hypochlorite to disinfect water is that a little goes a very long way. A 1-pound bag of calcium hypochlorite in granular form will treat up to 10,000 gallons of drinking water.

Just remember:

  • 1 cup or 1/2 pint=8oz;
  • 1 pint=16oz;
  • 1 quart=32oz;
  • ½ gal=64oz;
  • 1 gal=128oz;
  • 12.5 gal=1600oz

– Yukon Jon


  1. I’m not sure if this article is the original source, but it’s cited frequently on the web. The other article often cited says use 2 tablespoons per 3 or 4 cups of water. That is a HUGE difference in concentration than this article states. Anyone know which is correct?

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