Multiple Water Filters for Disaster Evacuation
Surviving in an emergency longer than a few hours will have a lot to do with your ability to acquire safe drinking water.
This is where a water filter
(typically used by backcountry hikers) can come in handy, and be a life-saver. Water filters are for the sole purpose of water purification. A water filter for the backcountry is light-weight, easily carried in a backpack, or in your car, and of course in every emergency kit (you'll have to add a backcountry water filter; most won't have one).
A good water filter (again, for the backcountry) can typically offer the most use and the longest life. Replacement filtration cartridges can help ensure months of safe drinking water.
Important Survival Tip: For multiple people consider multiple water filters, as a group of people using one water filter can slow you down on the trail or during an evacuation.