You can live without food for weeks but go without water for a week and you die…
In times of chaos using your good judgment goes out the window and panic and OMG sets in. Decision making becomes chaotic and scattered and this is not a time to lose your focus or you could end up dead.
One of the most important items you can have in your possession is an easy to use emergency water filter. You can spend hundreds of $ and get the most technologically advanced filtration system on Earth but if you cannot operate it when your stressed your screwed.
Determine how much water you will need to live. An average person requires about one gallon per day and can survive on ½ gallon if the need comes to that provided you are not exerting yourself.
Next is your budget, how much is enough? Will you spend $600 or $50 and get the same results?
I always look toward economy and simplicity and one water filter I really like that fits both of these parameters is the Sawyer Inline Water Filter.
Sawyer 34-ounce inline water filter which will process about 500 gallons of water these are a great choice too but get two (about – $35) . Able to filter enough water to sustain you for 6 months and longer.