The idea that water always conducts electricity is a common misconception. Pure water, composed only of H₂O molecules, is actually a poor conductor of electricity and acts more like an insulator. The danger of electrical shock near water depends entirely on the presence of impurities and the context of the environment. Understanding the distinction between pure and impure water is fundamental to appreciating the specific dangers posed by electricity in wet conditions.
Pure Water Versus Conductive Water
The ability of water to carry an electrical current relies on the movement of charged particles called ions. Distilled or deionized water contains virtually no dissolved solids or salts, meaning it lacks these mobile charge carriers and is therefore non-conductive. Pure water has an electrical resistivity of around 18.2 megaohms per centimeter, making it an excellent insulator.
Conductivity dramatically increases when water contains dissolved minerals, salts, and impurities, which create free-floating ions. These dissolved substances, such as sodium, calcium, and chloride ions found in tap water, are known as electrolytes. These charged particles provide the pathways necessary for electricity to flow, significantly lowering the water’s resistance and making it a conductor.
High-Risk Environments for Electrical Shock
The danger of electrical shock near water is realized when an energized source meets a conductive environment. Bathrooms are high-risk areas because electrical appliances like hair dryers or radios can fall into a bathtub, making the water, and the person inside, part of the circuit. Kitchens and laundry rooms also present hazards due to sinks and washing machines, where water spills or leaks can contact appliance wiring or outlets.
Outdoor settings are equally hazardous, especially where power tools, extension cords, or outdoor lighting are used in wet conditions. Faulty or damaged wiring in pool pumps or underwater lights can energize the surrounding water. If a live power line falls into a puddle or a flooded area, the water instantly becomes a path for ground fault current.
How Current Affects the Human Body
The severity of an electrical shock is determined not by voltage alone, but by the amount of electrical current, measured in milliamperes (mA), that passes through the body. A current of as little as 1 milliampere can be perceived as a tingling sensation. Currents above 6 to 30 mA can cause muscle tetany, preventing a person from letting go of the source, which increases the duration of the shock and the potential for injury.
The path the current takes through the body is also a determinant of damage. A hand-to-hand or hand-to-foot path is especially hazardous, as it passes the current directly through the heart. Currents exceeding 100 mA can cause ventricular fibrillation (V-fib), where the heart’s electrical signals become chaotic, stopping its effective pumping action. Wet skin drastically lowers the body’s natural resistance, allowing a greater current to flow through the body for a given voltage.
Essential Safety and Emergency Response
One of the most effective preventative measures against water-related shock is the use of Ground Fault Circuit Interrupters (GFCIs). A GFCI works by constantly monitoring the current flowing into and out of an electrical circuit. If the flow deviates by as little as four to six milliamperes, indicating a current leakage through an unintended path like a person or water, the device trips. This action interrupts the power supply in less than one-tenth of a second, which is fast enough to prevent a fatal shock.
If someone is actively being shocked, the first rule is to avoid touching the person, as this will make the rescuer part of the circuit. The immediate action is to turn off the power source, either by unplugging the device or shutting off the main breaker. If the power cannot be immediately cut, a non-conductive object, such as a wooden pole or plastic item, should be used to separate the victim from the source. Once the victim is free from the current, emergency medical services must be called, and cardiopulmonary resuscitation (CPR) should be administered if the person is not breathing or lacks a pulse.