Begin storing water IMMEDIATELY! and more useful tips in case of nuclear disaster
Lack of clean water will devastate your family much more quickly and more severely than any lack of food. Without water for both drinking and continued good sanitary practices in food preparation and for bathroom excursions (which will inevitably be much less sanitary than normal), debilitating sickness could rampage through your household with little hope of prompt medical attention. That is a highly likely but, avoidable, disaster, ONLY IF you have enough water.
Source: http://www.ki4u.com/guide.htm
Note: remember to print the guide as, in the case of this scenario, your computer will no longer work...
