It is extremely dangerous to swim when lightning is present. Since water is an excellent conductor of electricity, being in or on any body of water—whether a swimming pool, lake, or ocean—makes a person a direct part of that conductive path. Immediate caution is required the moment thunder is heard or lightning is spotted nearby.
Understanding How Lightning Interacts with Water
Water is an electrical conductor due to dissolved impurities and salts. When lightning strikes a body of water, the current rapidly spreads out radially across the water’s surface. In large bodies of water, such as oceans, the current tends to dissipate quickly, but the initial strike area and the immediate surrounding surface remain lethal.
In freshwater lakes and swimming pools, the risk is often greater because the current does not disperse as quickly as it does in saltwater. The danger to a swimmer is not limited to a direct strike, but also includes ground current that spreads across the water’s surface. For a contained swimming pool, the electrical charge can travel through the pool’s filtration, plumbing, or metal components. Even if the strike occurs some distance away, the water acts as a medium to deliver a potentially fatal electrical shock.
Safety Protocols for Water Evacuation
If a storm is detected, immediate compliance is required. If you are in or on the water, exit immediately and move away from the shoreline or the pool’s edge. The safest location is a substantial, fully enclosed building with wiring and plumbing that can safely conduct the charge to the ground.
Use the “30/30 Rule” to determine when to seek and maintain shelter. If the time between seeing the lightning flash and hearing the thunder is 30 seconds or less, the storm is close enough to pose a significant threat, and you must seek shelter immediately. Once safely indoors, wait a minimum of 30 minutes after the last observed lightning flash or sound of thunder before returning to outdoor activity.
When moving to a safe location, avoid contact with metal objects, which can serve as secondary electrical pathways. This includes metal fences, pool ladders, flagpoles, and large umbrellas. Fully enclosed metal vehicles, such as a car with the windows rolled up, also offer protection. Soft-sided shelters like tents, dugouts, or small sheds do not provide adequate safety.
The Risk of Water Use Indoors During a Storm
The dangers of lightning are not limited to the outdoors, as the electrical charge can follow conductive paths into a home. Lightning-related injuries occur indoors when the current travels through a home’s utility systems. Metal plumbing and water pipes act as a direct pathway for electricity, carrying the charge from an outdoor strike into the structure.
It is advised to avoid all contact with running water during a thunderstorm. This means refraining from showering, bathing, washing dishes, or washing your hands. Even if a home has plastic piping, the water contains minerals that make it conductive, and metal fixtures like faucets can still become energized. Wait until the storm has safely passed before using any water source or touching grounded metal surfaces.