Originally Posted by hercules_upw
You are correct
The resistance of ultra-pure water is 18.2 million ohms.
18.2 million ohms per what? If you measured the resistance of a tiny trail of many metres, then possibly. But it would depend on the voltage at which you measured the resistance...
The CONDUCTIVITY of pure water is about 0.055 ĶS/cm. You can't state the resistance of a substance unless you also state the exact size and shape of the sample, where your two measurement points are, either voltage or current (depending how you measure the resistance) etc... and even then, it's only the resistance of that sample, between your stated points.
Even tapwater is non-conductive enough to insulate... I know, I did the experiment...