Do not try to use water that has floating material in it, water that has any odor, or water that has a dark color. These are all indications that the water is significantly contaminated and may be dangerous no matter what you do to filter it or kill bacteria. On the other hand, a little dirt in the water can be cleaned out easily and won't hurt anyone.
If the water is cloudy, the first thing to do is take out as much of the dirt as possible. If you have time, start by letting it settle. Put the water in a tall container and leave it for 12 to 24 hours. Carefully dip or pour the cleaner water at the top into another container. Clean the water as you put it in the new container by running it through a filter. The easiest filter is a coffee filter. If you don't have a coffee filter, use a paper towel or a piece of clean t-shirt material or similar cloth. Change the filter whenever it gets visibly dirty.
Once water is filtered, it is fine for using to clean things like clothing and floors. Don't use water that you wouldn't drink to wash you face, rinse your dishes or clean the kitchen.
Once you have reasonably clean water, it has to be treated before it is safe to drink. The purpose of this is to kill all the germs that may be in the water. The Federal Emergency Management Agency and the American Red Cross agree on three acceptable ways to treat drinking water: boiling, chlorine bleach, or distilling. There are some other systems that can have problems. In general, these three are the best. Distilling is not practical for large amounts of water.
Water should be boiled for at least 3 to 5 minutes to sanitize it. Some agencies recommend boiling for 10 minutes just to be safe. If you live at high altitudes, add a minute for every 1000 feet above sea level. Remember that there will be evaporation and you probably want to cover the pot to retain as much of the water as possible. Once the water is boiled, let it cool in the same container. It can be put in storage bottles when it is cool.
Boiled water tends to taste flat because there is no air in it. You can add the air back by pouring the water back and forth between two clean containers. This will also improve the taste of stored or bottled water.
Boiling requires that there be a source of fuel and a safe way to store the water while it cools. If your kitchen is working, this is not a problem. If you are cooking over a grill or campfire, use bleach to purify the water.
If you are treating the water to cook with, do not add the food until the water has boiled for the amount of time needed to treat the water. There is no need to boil the water, cool it and then reheat it for cooking, but you may contaminate the food if the water has not boiled long enough before using it to cook. If you put food in contaminated water, it gives the germs a place to hide and they may not be killed in the amount of time needed to cook vegetables or pasta.
The biggest problem with boiling for water treatment is that you can't treat very much water at a time. Most kitchens don't have any pots bigger than 6 or 8 quarts and you can't fill them more than about half or two thirds full. Remember that boiling water is a safety issue. Even fairly small burns can make you very sick if they get infected.
Treating water with bleach is very effective at killing germs and it doesn't taste funny to most of us because this is basically what most city water supplies do. You need to have a bottle of plain liquid chlorine bleach and a dropper. The bleach should be 5 to 6 percent sodium hypochlorite with no preservatives and no additional ingredients. Do not use scented bleaches, color safe bleaches, powdered bleaches, or bleaches with added cleaners. You want the good old fashion stuff that smells like chlorine and burns holes in your clothes if you pour it right on them. Even this is hard to choose because it is now available in different concentrations. Ultra Clorox is a 6% solution instead of 5.25% but it is the same stuff. Keep a bottle of plain 5.25% or 6% chlorine bleach with no additives in the laundry room to use for water purification. Besides, this cleans sweat socks as well as any of the others.
To treat water with chlorine bleach, put the water in a clean container and add 16 drops of bleach for every gallon of water. Stir in the bleach and let the water stand for 30 minutes. If the water does not have a little smell of bleach, repeat the dosage of 16 drops per gallon and let it sit for another 15 minutes. If it smells of bleach now it is OK to drink. If it doesn't smell of bleach after two treatments, the water is too dirty to use. Throw it away and treat a new batch of water.
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