I've been rolling around survivalist boards, prepping boards and so on for a lot of years, and there is a common idea that I've seen over and over--that in the event of a major SHTF event there will be "golden hordes" of bandits, roving inner city gangs fanning out into the countryside, groups of cannibalistic mutant zombie bikers roaming all over creation or just lots of hungry folks looking for a meal killing off the remaining good folks for their stuff.
While it may happen here and there, I think this is another place where our fears are leading us down the garden path, and for a simple reason--clean drinking water and the availability of it.
At this point, I figure anyone that is into the subject has head about the "rule of threes". It comes in a lot of formats, but the one I have came up with is that you die after 3 minutes without breathing, that you will freeze to death in 3 hours of bad weather and that 3 days without water or 3 weeks of not eating you will be unable to do anything except finish dying.
Obviously, there is a lot in that that can be debated, but I want to talk about the water issue, because that's the one I believe will be the limiting factor in this whole roving gang thing.
It's a historical fact that water-borne diseases are big killers of mankind. Before we discovered the existence of germs ("the germ theory of disease"), typhoid, typhus and cholera were a fact of life and killed people every day. Even after we figured out the germ thing, people still died from those diseases, and they still die from them today. It seems to be rather difficult to get the concept of "Don't shit in the drinking water" across to some people. And this will be an important point in a SHTF event.
We are all utterly conditioned to do our business in the toilet and flush it away, and that works as long as the power is on, the water flows and the sewers are open. Turn off the power, and within 24 hours the water tanks will be empty. Most people with private wells have no backup power for their pumps and no alternative to the electric pump to get water out of the ground. In areas where sewage must be pumped to treatment plants (or for folks with septic systems that have macerater pumps), the sewer will start backing up even sooner. So within 24 hours, 48 at most, both safe drinking water and the easy ability to dispose of human wastes will be in very short supply.
In cities and towns across America, most people will not know have a clue how to deal with this situation. They will have no clue how to safely dispose of human waste, no clue how to purify water and likely little access to any water to purify.
Imagine this suburban scene: A hypothetical suburban family in a hypothetical suburb--Mommy and Daddy and kids. It's been 3 days since the power went off, and 2 days since the water ran out. The stench from unflushed toilets would gag a maggot. It's 90 degrees and our hypothetical suburban family lives in a house that was designed to be air conditioned. Sounds pleasant, doesn't it?
So Dad is at least moderately resourceful. He manages to get the waste out, and like his neighbors, tosses it into a ditch somewhere. You know, the ditch where the rain runoff flows to the local creek or pond. We have some air freshener, and that plus the last of the window cleaner and paper towels gets the worst of the smell gone.
But gee, we're thirsty. The wife is bitching continuously and the kids are crying. All the water and soda is gone, not that there was that much anyway. Why store food when the grocery store is right down the way? Except that now, the grocery store is empty.
But gee, there's the creek. So Dad grabs a bucket and, like his neighbors, all of whom are in the same boat, manages to get a bucket of water with only a little dirt in it. He takes it home, triumphant. Except he knows that this stuff needs to be cleaned up. Hey, the city filters the water, right? So he gets the coffee maker, takes the filter basket and starts running the water through it into glasses. Clean water for everyone!
Twelve hours later the diarrhea has hit everyone hard. The toilets don't work, so they do their business in whatever buckets are handy. They're too weak to go far, so it gets dumped in a corner of the yard. The kids die first, followed by Mommy and finally Daddy.
Think it won't happen? Then I fear you over-estimate the survival knowledgebase of the average American. Don't believe me? Conduct this experiment--ask a dozen people you know how to take a bucket of random water and make it safe to drink. See if you get any correct answers. I have; it's depressing.
Oh, and after this sad episode? A thunderstorm shows up and all that raw human waste is washed into the local rivers and streams.
Personally, I figure if you can make it 30 days, the worst of the population die off will be over. But you'd better stock up on water purification gear if you want to make it.