Water consumption torture used to be used on pirates or noncompliant sailors back in the days of Jack Sparrow and other legendary people I know. And this is the good ol' British navy doing it for fun, and from my history lessons at school as opposed to wiki.
They used to tie a naughty chap to a mast, and force him to drink water slowly but constantly via a tube down his still conscious gullet. As above, salt depletion would make them go wacko first (low sodium) before the kidneys became fully porous, and the blood juice just drained out of him, followed relatively quickly by seizures coma then being buried at sea. Because you start peeing for lack of control before the kidneys give up, which is incredibly painful if you have ever had a kidney infection. So the more you pee, the more you start to crave the water, and it becomes a vicious cycle where in essence you are drinking water to die. Excellent.
I've added in some medical stuff to make it look even more fun (accurate stuff mind), but it's a horrible way to go and very painful to the muscles everywhere, as well as feeling like you are being run over across your midsection, without going into a whole homeostasis explanation of sodium, pot, carb, etc balance explanation.
Before you died though, they would often stab you as well, just for a bit of sport. Bless the old royal navy eh?!
I have probably sounded quite evil now from the above. I am.