ok so I went out to put a few bullets down range at a friends place about a week ago when it warmed up for those few days. well it was muddy so I drove my truck back to the range. well long story short I needed the extra room in the cab for some others and I put my BOB in the bed of the truck. well I forgot to put it back in the truck that night and it rained during the night. when I got up the next day I noticed that I forgot to put it back in my truck. so this got me to thinking that if I was in need of this bag and it would be raining if the SHTF that it would be good to make sure they can resist the rain. Now the bag that I have is a military bag so it did pretty well but some water did get in. so the lesson learned is to put some water proofing spray on the bag like scotchgard. I know some people are reading and going duh. but if I helps someone out I am glad.