What do you do if sombody was rescued from the water and is unconscious?

I'm a certified lifegaurd, and there are many answers to this question.

There are three types of drowning victims.

Passive drowning - victim is not moving in water. May be submerged.

Active drowning - someone who is struggling in the water, head bobbing under and struggling to stay afloat.

Spinal drowning victim - someone who is passive and has suffered a spinal injury. NOTE: UNLESS YOU ARE CERTIFIED, DO NOT ATTEMPT TO MOVE THIS PERSON AT ALL, UNLESS THEY ARE SUBMERGED AND NEED TO BE BROUGHT TO THE SURFACE FOR AIR.

You really should be certified to perform rescues on these victims - look into a lifeguard certification program in your area.

"Treatment" is really to generic a term. If they are unconsious once you pull them out and have no pulse or breathing, check their airway to see if they have an obstruction and they are choking. If the airway is clogged, do the Heimlich and back blows. If it is clear, start CPR. If they have a pulse and no breathing, breath for them, by pressing your mouth to their face and giving them a long breath, pulling your face back, counting to 3, and giving them another long breath. Do this for 40 breaths, and check if they are breathing on their own.

If they are consious, and coughing and sputtering, encourage them to do so, and they'll be fine. Just keep them warm after that.

But you really should be certified