If you want to see how strong society is turn off the water supply, and leave it off. Never mind the power.

In most areas, if the power is off for more than a few weeks, the water goes off to because the pumps stop running.

What's that supposed to do, exactly? Worst case is you buy $1 gallons of water at the grocery store for a while and don't shower.

The grocery stores will run out of water in the first few hours. That is, every single grocery store. Now what was that again about worst-case?

Great, now that people are supplied for a couple days let's get into the meat of it. People with wells can supply their neighbors and sell excess water for a nice profit, the police and fire department can take over the reservoirs and help with transport and filling containers...

Okay considering the downvotes I suppose I should have laid out my point at first: We use far far more water than we actually need. In an emergency situation it's not extremely hard to get a couple of gallons a day to people.

Unless by water supply we actually mean turn off the rain. I have no response to that one. That's not going to impact society, that's going to kill almost every bit of land life across the entire earth.

And don't use the bathroom?

Humanity got by for quite a long time without flush toilets. That would be relatively low on my list of concerns.

Humanity got by without a lot of things for a very long time. But around 1800, the population begun to climb. After taking 200,000 years to reach our first billion we, reached our seventh just 200 years later. A sudden reversion to the conditions known by America's Founding Fathers would leave ~7/8th of the global population unsupported.

So yes, flush toilets would be the least of your concerns, what with the zombie apocalypse in full swing and everything.

Flush whenever you want, costs you half a gallon. Is this supposed to be a real objection?