[Spellman]

Luckily we have equations for this!

Assume that the water has a fixed resistance of R. You have increased the Voltage V about double.

As a result of V=IR, the I, or current flow, will be doubled. Which in this case is probably a moderate tingle since R is so high.

For reference, the heart muscles start getting involuntary twitches around 100mA, and at 200mA causes cardiac arrest. And the standard units of Voltage, Amp, and Ohm will serve you well here for any conversions.

[pvillano]

You'll get the same tingle at a greater distance. In fact, if the current is finite and current density decreases with distance, it is bounded by the inverse square law.

240v will give you more distance to react between the tingle radius and the kill radius