Storing water - What to put it in--Camping cans, plastic cans and buckets, 15, 30 and 55 gal. drums. Add siphon hose or siphon pump. Water heater, bathtub, toilets and sinks are all good storage vessels. Be careful that you don't store it where it will freeze in cold weather. Save wash water for flushing toilets.
Obtaining water -- Irrigation canals, drainage ditches, at culverts, rain gutters, etc. Catch dew and rain. Build a solar still.
Filtering and purification --It's hard to store enough for long term. Family of 4 needs minimum of 120 gallons for 1 month. More for cooking and personal hygiene.
Filtering -- Filtering units and portable bottles. Filtering does not always mean purifying and vice versa. Make sure that you have made provisions to to both filter and purify any water that you have to get from questionable sources
Purifying -- Boiling, iodine, chlorine, Colloidal Silver, filters like Katydyn.
If you purchase commercial filters, here are the approximate sizes of the things that need to be removed from the water. Viruses (hepatitis, polio, etc)- .02-.2 microns, Bacterias (e-coli, salmonella, cholera)- .2-.5 microns, Protozoans (Giardia) 1.0-1.5 Microns.
1. Iodine - Put 5 drops in a quart of clear water and 10 drops cloudy or ice cold water, stir and let stand 30 min.
2. Chlorine - Use regular, unscented chlorine bleach such as Clorox or Purex. Put 2 drops per quart of water, 8 drops per gallon or ½ tsp. per 5 gallons of clear water and double if water is cloudy or very cold. Iodine is a little more effective than chlorine. Chlorine is not effective against Tuberculosis or Giardia and is also a carcinogenic.
3. Boiling- Boiling is the most certain way of killing all microorganisms. There is considerable controversy about how long is long enough to boil water to be 100% effective. One commonly accepted method is to boil for 1 minute at sea level and add 1 minute for each additional 1000' of elevation.
Water temperatures above 160° F (70° C) kill all pathogens within 30 minutes and above 185° F (85° C) within a few minutes. So in the time it takes for the water to reach the boiling point (212° F or 100° C) from 160° F (70° C), all pathogens will be killed, even at high altitude. To be extra safe, let the water boil rapidly for one minute, especially at higher altitudes since water boils at a lower temperature.
4. My personal favorite these days is colloidal silver. It is much more effective and faster than either chlorine or iodine. Add 1 tablespoon of CS per gallon of water, shake, wait 6 minutes, shake again and drink. ½ teaspoon per gallon is recommended but as cheap as CS is to make, I use a little more to be sure.
5. Commercial purification tablets are available at most sporting goods stores and are accompanied by directions.