But the negative ions are pushed away and the positve charges are pulled to the baloon. So, like in a capacitor there is a charge separation. But I dont understand how there is a net movemnt of the whole stream.
My hypothasis is that the friction between the water and the pipe caused to the water to be positivly charged, and thus to attract to the negative baloon.
Because the positive charges are closer to the baloon than the negative ones