You can only live three days without water.  So, finding drinkable water is a priority in outdoor survival.  Streams and rivers may not be safe to drink.  So, you need to take steps to assure that your water source is purified.  This video will guide you in treating  water.

 

This is great advice.  But, I would also highly recommed that you check out the LifeStraw. The, portable, LifeStraw is a great way to safely drink clean water in all situation.  All you do is place a straw into water and drink.

Click Here for more info.