The science that keeps our heart moving is the same science that keeps their fluid sacks not shriveled or exploding. The concentrations of ions/salts on each side of the membrane creates a difference in voltage across the cell membrane, which creates potential energy. if that goes to equilibrium the cell is dead.

Idk if electricity would kill what’s in the water, but if you do something to the water to make the difference in voltage across their membranes become zero, they are essentially dead. It would be hard to calculate a voltage and duration or whatever to make every singe membrane in your sample go to equilibrium. Idk dammit Jim I’m a dietitian not a mad physics professor.

Also, not everything needs to be living to be dangerous. Many pathogens make things that cause us illness, if that thing is still in the water even after the microbe has died, we still get sick. And there are inorganic things that can make us sick, also. Plus spore-forming bacteria could die but leave tough little spores behind waiting to respawn. So..ya. Now I’m having physiology flashbacks and I’ll probably have nightmares on differentiating calcium channels.