Now that might seem like an overstatement, but follow for a moment... You have two parallel systems, one clean and one dirty. There's the input, be it a well, reservoir, river, or whatever. It feeds into some big pipes which slowly split into countless smaller pipes. Then there's the output, combining into a big outflow somewhere down the line.
You might think of water mains and sewers as major arteries and veins, becoming capillaries in the smaller pipes of our houses. Clean water is pumped into the system with force, rather like blood is under greater pressure in the arteries. Dirty water, flushing away our waste, tends to be under low pressure and flows from the simple pressure of expulsion after being used.
I think what amazes me is the simultaneous complexity and simplicity of the system. Think about it -- all those pipes are directly connected, except for the brief moment where the water reaches daylight in our sinks, showers and toilets. Heck, a lot of water doesn't even see daylight at this point. It comes into a dishwasher or washing machine, gets all dirty, and then flushes out to the system.
There are pumping stations, and if you look at the purification systems on either end, there's a lot of technology involved, but the basic system is just a bunch of pipes which we all agreed will work a certain way. To me, this shows the remarkable way that humans work together without even knowing it.
You pay your water bill, and it's "your" water once it moves past your meter, just as it's your waste leaving the organ you call your home. But we all share in the system without any more thought about it than you give your own digestive system. Heck, probably less. You turn a knob, and you have a glass of water. You flush your toilet, and your waste is gone to be someone else's problem.
Perhaps it's the sign that we are all just part of a greater organism. Perhaps we model our systems off our own biology. I don't know. But I don't take it for granted. Our cities, our culture, and our civilization wouldn't be able to exist with this elegant system.
And maybe I'm a little overawed by something that's such a simple part of life. But, to me, it's these things that we miss every day and, silly as it sounds, if we're all just a little more aware of the complex, amazing systems that keeps us alive, maybe we can be a little more aware of life in general.
Or maybe I just spend too much time on the can...