If you have the right iodine you can purify your own water, long range hikers do it all the time, not easy for long haul..... but you can boil it.
I prefer a combination of filtration (Berkey, Katadyn) and bleach stock made with Calcium Hypochlorite (pool shock)
http://survivaltopics.com/better-than-bleach-use-calcium-hypochlorite-to-disinfect-water/
POLAR PURE® WATER TREATMENT
For a low cost way to treat questionable water to make it safe for drinking Polar Pure is once again available.
Ideal for camping, hiking, car broke down, bailing out, etc.
Polar Pure® was forced off the market by the federal government several years ago because drug manufacturers were using the chemicals it contains to make drugs. The Polar Pure® manufacturer has finally been able to institute controls that satisfy the government and has brought the product back on the market.
Polar Pure® isn’t the long term answer to providing large quantities of safe drinking water for your family but it is perfect for the short term, bailing out, emergency carry bag, camping, storm and power emergencies, etc.
One $20.00 bottle of Polar Pure® treats up to 2,000 quarts of water.
POLAR PURE® GEAR REVIEW:
http://www.backpacker.com/gear/essentials/water-purifiers/gear-review-polar-pure-water-disinfectant/
BUY POLAR PURE® HERE:
HISTORY: WHY THE GOVERNMENT FORCED POLAR PURE® OFF THE MARKET:
http://www.mercurynews.com/ci_19385037