Drowning is a major public health issue that can be prevented.  

1.  Learn basic swimming and water safety skills.

2.  Build fences that fully enclose pools.

3.  Supervise children and vulnerable ones closely.

4.  Wear a life jacket.

5.  Learn CPR.

6.  Know the RISKS of the natural waters where you are swimming.

7.  Avoid alcohol.

8.  Use the buddy system, children and adults.

9.  Take additional precautions for medical conditions and the effects of medication.

10. DO NOT hyperventilate or hold your breath for a long time.  This can cause you to pass out and drown.  This is sometimes called "hypoxic blackout" or "shallow                water blackout".

Information taken from the center for Disease Control and Prevention/drowning prevention