Regardless of what you call a Survival Water Filter, you definitely need one. Survival Water should be at the top of your Survival list. You should consider purchasing the Best Water Filter you can possibly afford. Because without Water ... you're toast.Will city Water be available to you during an extended Survival event? Probably not. So a means of treating your Survival Water becomes paramount. While it's true you can boil your Water, that's not always possible. Purchase a Water Filter to treat your Survival Water. You'll be glad you did. And don't forget ... you'll need something to carry and store your water in.