How to Sterilize Water. Most Americans are accustomed to an uninterrupted source of not only water, but water that is free of bacteria, fungi or any other teeny, tiny "uglies." We are, of course, spoiled in this regard. Water supplies can be affected by floods, disruptions in water lines and a variety of other unexpected events. It's not a bad idea to know how to create a supply of sterilized water, free from unwanted guests.
Realize that boiling water does not sterilize it. There are bacteria that form spores that are resistant to boiling and some strains of bacteria that are themselves resistant to heat above boiling temperatures.
Use a pressure cooker. Place a bottle of water in a pressure cooker. Make sure that there is no cap on it or that the cap is loosened so it does not burst under pressure. Cover the cap with a piece of aluminum foil to prevent bacteria from accumulating around the mouth of the bottle at a later date. Heat the water to 121 degrees for 20 minutes. Slowly release the pressure. Let the aluminum foil cool. Close the cap and fold down the aluminum.
Use chlorine to sterilize water. Let water stand until particles in the water settle. Pour off the clear water into a clean, uncontaminated container. Add two drops of Clorox bleach for each quart of water, eight drops of Clorox bleach for each gallon of water or ½ tsp of regular Clorox bleach per 5 gallons of water. If the water is visibly cloudy, double the amount of Clorox.
Utilize the effect of ultraviolet radiation on the most common pathogens. This is of particular use if you are in a circumstance where large amounts of sterile water are needed and you have few resources. Pour off particle matter. Take the clear water and pour it into a clear plastic bottle. Place the plastic bottle on a dark surface. Leave the bottle in sunlight for at least eight hours. The combined effect of ultraviolet radiation from sunlight and heat is effective in producing a primarily safe source of drinking water.
Use a 2 percent tincture of iodine to sterilize water. Add 12 drops of the solution to every gallon of water to be sterilized.