It is never safe to drink water from a source that has not yet been treated or you are unsure of. (For Example: water from a stream, lake, river, pond etc.) These sources of water especially could be contaminated with a variety of biological or chemical contaminates, including bacteria and parasites (such as Giardia) that may cause diseases such as dysentery, cholera, typhoid, and hepatitis. There are many different methods that can be used to treat a contaminated water source; among the most common and effective ways are boiling, filtering, and using chemical treatments. In an emergency situation where you are forced to evacuate, your resources will be limited. You might not have fuel or supplies available to burn for fire, and if you aren’t prepared with a water filter, chemically treating your water is your best option. There are a few ways to chemically treat water if the supply you have is not deemed ‘drinkable’. These are some of the most common ways to chemically treat your water: Chlorinating Water with Bleach - In this method water should be treated with bleach. Add 1/8 of a teaspoon (8 drops) of liquid household chlorine bleach (5 to 6% sodium hypochlorite) for every gallon of water. (4 liters) Use only house hold bleach without thickeners, scents, or additives. Using Iodine - Iodine is a little better than chlorine at eliminating Giardia, however it’s more difficult to carry and is not for everyone. Iodine must be stored in a place where no light can enter, and another downside is that anyone who is allergic to iodine, has thyroid problems, is on lithium, is a woman over 50, or is a pregnant or nursing woman, should be very careful and caution their doctor before using iodine. Generally iodine works best when the temperature of the water is warmer (at least 68 degrees F). If you are using a liquid preparation of 2% tincture of iodine, add 5 drops to a quart of clear water or double that if the water is cloudy. Shake well and let stand for an hour. Specialty Products on the Market - There are many products that are specifically meant to preserve or treat water for storage or immediate use on the market. These come in the forms of drops, tablets, pouches, and more. When using one of these methods, always follow the instructions directly on the packaging. Most of these products will purify the water within 20 minutes to a couple of hours. It will always maximize the life span of the purified water if you store it in a cool place where it will never receive direct sunlight.