Survival water purification filter and tablets. Staying hydrated and having clean drinking water in all situations is essential for surviving. Read my article How to Get Clean Water in an Emergency. You'll need store water and have water filters and water purification tablets always ready. Water Purification. Once you find water, a major issue remains: is it pure? Is it drinkable? And if not, how to make it drinkable? For short term needs it's essential to have hydration backbag, so you have always drinking water for instant need.