Final answer:
To start CPR on a victim found in water, first bring them to stable ground, check their airway, and then begin chest compressions between the T4 and T9 vertebrae at the correct depth and rate.
Step-by-step explanation:
When starting CPR on a victim found in water, the initial step is to safely remove the person from the water. CPR is ineffective in the water and must be performed on stable ground. After ensuring the airway is not sealed by the muscular spasm of the larynx, which can occur during drowning incidents, begin CPR immediately if the person is not breathing or if their heart has stopped. Position your hands on the sternum between T4 and T9 vertebrae and perform chest compressions at least 5 cm deep at a rate of 100 compressions per minute. It's important to note that proper training is essential for administering CPR to prevent causing harm such as broken ribs or other injuries.