[CamperBob2]

Interesting idea. If the water were conductive -- say salt water -- then I don't see why you couldn't steer it with magnets. The trick would be to keep an electrical current running through the jet.

At normal fluid pressures -- the classic example being peeing on an electric fence -- it's hard to get much current flowing since there's so much empty space between droplets. But at thousands of PSI, is that still true?

[JshWright]

Water is dipolar (the oxygen atom 'pulls' harder on the electrons it's sharing with the hydrogen atoms, so the middle is negative and the ends are positive). It can be controlled by both electrostatic and magnetic fields, no salt needed.

[CamperBob2]

Electrostatic, sure. You can deflect a stream of water from a faucet by holding a comb near it. But magnetic?

[gambiting]

This sort of thing was actually used for water propulsion system:

https://en.wikipedia.org/wiki/Magnetohydrodynamic_drive