When disaster strikes there may not be enough clean water on hand to drink. This is why part of emergency preparedness is to have numerous bottles of water on hand as well as water purification tablets.
The best type of water purification tablets are those that rapidly dissolve in water. These are iodine-free tablets that are effective against the cyst cryptosporidium, giardia, bacteria and viruses.
Most people can use rapidly dissolving iodine-free tablets called Aquatabs. These are the tablets used by Oxfam, The International Red Cross, NATO, WHO, UNICEF and Sans Frontiers. The reason these tablets are used by so many agencies is because they are safe for adults as well as pregnant women and children.
The cost for this type of water purification tablet is about twenty bucks for fifty. Each tablet treats about one liter of water. You must let the tablet sit in the water for half an hour before it safe to drink. It is a good idea to shake the bottle and then open it to get rid of a gassy or toxic smell of chlorine.
Water purification tablets have no smell and do not color the water. They also will not stain plastic bottles. Another good thing is that they are portable which is why hunters, trekkers and hikers carry water purification tablets with them on long journeys.
One thing that water purification tablets are not effective against is particulates in the water. Be sure to filter the water as best you can before you treat it with the water tablets.
Perhaps one of the most effective ways to treat water is with a water filter pump like the MSR Miniworks pump. These pumps are effective against protozoa and larger bacteria. They also can help reduce concentrations of chemicals including the presence of iodine and chlorine. If you use a combination of this filter plus the water tablets then you substantially reduce the odors and tastes of unfiltered water. They have a pump attachment that looks like a trigger for pumping water into the bottle and a foam filter plus plastic filter inside. You can then empty that water into any wide-mouthed plastic water bottle.
An older but effective form of water purification contains iodine with chlorine dioxide. You add liquid drops into stages to the contaminated water to purify it.
If possible avoid water treatment tablets that have iodine in them and opt for cleaner types instead.