“If you feel a shock, swim away from the dock,” is a good thing to remember when swimming. Knowing what to do if water becomes electrified can help swimmers avoid an invisible hazard called electric shock drowning (ESD).
Outdated wiring and a lack of proper safety equipment on boats and docks can cause situations where electricity seeps or leaks into the water. It is a particularly dangerous hazard because it is impossible to tell by looking if water is energized. According to the Electric Shock Drowning Prevention Association, between 10 and 15 milliamps, which is just 1/50 the wattage of a 60-watt lightbulb, can cause drowning.
Safe Electricity recommends that individuals do not swim around docks with electrical equipment or boats plugged into shore power. If you are in the water and feel electric current, shout to let others know, try to stay upright, tuck your legs up to make yourself smaller, and swim away from anything that could be energized. Do not swim to boat or dock ladders to get out.
If you see someone who you suspect is getting shocked, do not immediately jump in to save them. Throw them a float, turn off the shore power connection or unplug shore power cords. Try to eliminate the source of electricity as quickly as possible, then call 911 for help.