The following is the text from a full page ad by Clorox .
Boiling Is Best
Short of using a very high-quality water filter, this is the most reliable method for killing microbes and parasites. Bring water to a rolling boil and keep it simmering for at least several minutes. Add one minute of boiling to the initial 10 minutes for every 1,000 feet above sea level. Cover the pot to shorten boiling time and conserve fuel.
Liquid Clorox Bleach
In an emergency, think of one gallon of Regular Clorox Bleach as 3,800 gallons of drinking water.
When the tap water stops flowing, Regular Clorox Bleach isn't just a laundry-aid, it's a lifesaver. Use it to purify water, and you'll have something to drink.
It's the same in any natural disaster. As the shock wears off and the days wear on, the biggest demand is for drinking water. Time after time, relief crews hand out free Clorox Bleach with simple instructions: use it to kill bacteria in your water and you'll have purified water to drink. Here's how: (Store these directions with your emergency bottle of Clorox Bleach.)
First let water stand until particles settle. Pour the clear water into an uncontaminated container and add Regular Clorox Bleach per the chart.* Mix well. Wait 30 min. Water should have a slight bleach odor. If not, repeat dose. Wait 15 min. Sniff again. Keep an eyedropper taped to your emergency bottle of Clorox Bleach, since purifying small amounts of water requires only a few drops. See chart* suggestions for storage bottle replacement.
Don't pour purified water into contaminated containers. To sanitize water jugs first, see instructions** below
Without water and electricity, even everyday tasks are tough. In lieu of steaming hot water, sanitize dishes with a little Clorox Bleach. Just follow the directions below to keep dishes clean. After its work is done, Clorox Bleach breaks down to little more than salt and water, which is good news anytime.
*Ratio of Clorox Bleach to Water for Purification
2 drops of Regular Clorox Bleach per quart of water
8 drops of Regular Clorox Bleach per gallon of water
1/2 teaspoon Regular Clorox Bleach per five gallons of water
If water is cloudy, double the recommended dosages of Clorox Bleach.
(Only use Regular Clorox Bleach (not Fresh Scent or Lemon Fresh). To insure that Clorox Bleach is at its full strength, replace your storage bottle every three months.)
**Clorox Bleach Sanitizing Solution
Mix 1 tablespoon Regular Clorox Bleach with one gallon of water. Always wash and rinse items first, then let each item soak in Clorox Bleach Sanitizing Solution for 2 minutes. Drain and air dry.