If I was really concerned about disaster preparedness I think I would focus on Berkey style of water purifier (not filter). I would though also supplement it with iodine or any chlorine purification product that has very long shelf life ( which in general forces you back to iodine).
Regrettably Polar Pure that was based on this paper is no longer available. On the other hand my 20 year old bottle should be good far at least another 250 gallons of water treatment.