Aye .. You need to charge water with electricity to extract Hydrogen (Add chemicals to stop it sludging up the electrodes) .. Then burn it with oxygen and it produces H20 .. Pure Distilled water would produce Hydrogen & Oxygen. Burn Hydrogen with normal air would work also.

You could have pre-pressurised hydrogen fuel (Dangerous) or you could convert it pre burn but it woulds use more electicity to produce than technology could convert .. Still a few year away .. But MERC have a sprinter that blows out hot water ..