[5th MEB]

Unless you are getting your water downstream from a chemical waste dump or contaminated mine tailing's; the chances of you being able to drink enough naturally, chemically, contaminated water to cause you any harm as close to 0 as makes no difference. Now remember we are talking about fresh water, not salt or sea water here. All natural water is contaminated with chemical and mineral contaminants; it is the nature of the beast, water is the perfect solvent and over time it will dissolve any thing. The biologicals in water are the true danger to some one in the field and proper precautions should always be taken.

[Kartographer]

The big problem out here in western states is natural occurring arsenic The method effectiveness also a depends on the water’s turbid. When the water is highly turbid, SODIS can not be used alone, additional filtering or flocculation is then necessary to clarify the water prior to SODIS treatment.

I would consider this method for use with rain collected water, springs or water from fast moving streams and brooks with a very low turbid. For example the major source (and almost the only sure year round source) of water here is the river which is filled with all sorts of debris and possible chemicals and so I would not use this method. If I made up into the mountains a hour north are a number of springs and fast running creeks that this method would be sufficient for.

But a good filtering system is usable for just about any water you can find, Nothing wrong with having multiple ‘tools’ in your ‘tool box’ I just wouldn’t depend on this sytem as my primary means of purifying water.