IMPORTANT: Water contaminated with fuel or toxic chemicals will not be made safe by boiling or disinfection. Use bottled water or a different source of water if you know or suspect that your water might be contaminated with fuel or toxic chemicals.
In emergency situations, use bottled water if possible; bottled water is the safest choice for drinking and all other uses. If bottled water is not available, the following methods can help make your water safe to drink.
If you don’t have safe bottled water, you should boil your water to make it safe to drink. Boiling is the surest method to kill disease-causing organisms, including viruses, bacteria, and parasites.
You can improve the flat taste of boiled water by pouring it from one container to another and then allowing it to stand for a few hours; OR by adding a pinch of salt for each quart or liter of boiled water.
If the water is cloudy:
If you don’t have safe bottled water and if boiling is not possible, you often can make small quantities of filtered and settled water safer to drink by using a chemical disinfectant such as unscented household chlorine bleach.
Disinfectants can kill most harmful or disease-causing viruses and bacteria but are not as effective in controlling more resistant organisms, such as the parasites Cryptosporidium and Giardia. Chlorine dioxide tablets can be effective against Cryptosporidium if the manufacturer’s instructions are followed correctly.
Many portable water filters can remove disease-causing parasites such as Cryptosporidium and Giardia from drinking water.
If you are choosing a portable water filter:
Try to pick one that has a filter pore size small enough to remove parasites (such as Giardia and Cryptosporidium). Most portable water filters do not remove bacteria or viruses.
Carefully read and follow the manufacturer’s instructions for the water filter you intend to use.
After filtering, add a disinfectant such as iodine, chlorine, or chlorine dioxide to the filtered water to kill any viruses and remaining bacteria.