So there I was, minding my own business, when my daughter comes into living room, and tells me 'Dad...there is a lot of water on the floor in laundry room...and it looks like it is spraying down from the ceiling'.
Well...that gets a reaction. There was a lot of water on the floor in the laundry room(and seeping into the family room carpet)...but the good news is that it was coming out the plastic tubing running to the ice machine, and not from some other more horrifying source.
That is where the good news stopped.
I followed the tubing back to it's source...and yay! there was a valve!
However...when I shut the valve, the water didn't stop. First off...the little needle valve was tough to turn...I actually put a crescent wrench on it to turn it...and when I reached the torque point where I started to worry that I was going to snap the valve body...I stopped torqueing, and started looking upstream for another valve to shut.
There wasn't one...other than the main shut-off valve coming into the house.
Some idiot(I'm assuming it was the previous owner), installed a self-lapping saddle valve on a portion of piping that there was no other way to isolate.
I didn't know it was a 'self-lapping saddle valve' until I got to the hardware store with my pictures to find a solution to the problem. The short-term solution was closing the house shut-off valve...which I did when I found out the needle valve didn't stop the flow. Long term...well, I was hoping I could replace the valve, but...when I got to the store and saw how a saddle valve worked, that didn't seem like a good plan. Instead, I went with plan 'B'...disconnect the fitting where the tubing goes in, and cap that off.
Mission successful. I restored water to the house, and the kids got to brush their teeth before bed time.
It still looks like there is no long term solution...I will just have to check the cap I installed every so often to make sure it doesn't start leaking.
What a stupid design.
Even Wikipedia tells you to stay far, far away from saddle valves.