Taking a bath or shower during a thunderstorm is highly unsafe and should be strictly avoided. Lightning is a massive, rapid electrical discharge that can travel through a building’s plumbing system, even when the strike occurs outside the home. Lightning seeks the path of least resistance to the ground, and your home’s infrastructure can inadvertently provide that pathway. Engaging in water-based activities significantly raises the risk of electrocution.
How Lightning Enters Your Home
A cloud-to-ground lightning bolt’s objective is to find a low-resistance path to the earth’s surface. While a direct strike to a house is possible, the more common risk comes from the electrical current entering the structure through external utility connections. Utility lines, such as those for power, telephone, and cable television, are often grounded outside the home and can act as conduits for lightning energy.
Lightning can strike a utility pole or the ground nearby, creating a surge that travels along these service lines directly into the house’s internal systems. The immense current, which can reach tens of thousands of amperes, then looks for a continuous pathway of conductive material to complete its circuit to the ground. This search for the path of least resistance often leads the charge through the home’s electrical wiring, phone lines, and crucially, the plumbing system.
Internal Current Travel
Once inside, the current can “side-flash,” jumping through the air from one conductive material, like electrical wiring, to another, such as water pipes. This means that internal systems can become energized by a nearby strike, even if the lightning does not directly hit the plumbing.
Plumbing Materials and Electrical Risk
The bathroom environment poses a specific danger because of the materials used in plumbing and the conductivity of water. Water is a conductor of electricity, meaning that a person in a bath or shower acts as a bridge between the energized plumbing system and the ground. Even if the water itself is relatively pure, the impurities and minerals commonly found in tap water increase its ability to carry an electrical current.
Metal pipes are excellent conductors, readily transmitting the electrical charge from a lightning strike that has entered the home. If lightning strikes a water pipe, the electricity will move along the metal, and a person touching a faucet or standing in the water can complete the circuit, leading to electrocution.
The risk remains even in homes with modern plastic (PVC) plumbing, as the electrical charge can still travel through the water itself. Furthermore, the water supply source, such as a well pump or the main municipal lines feeding the house, often still involve metal components that can become energized.
Essential Storm Safety Guidelines
The safest course of action during any thunderstorm is to avoid all contact with water and electrical conductors. The Centers for Disease Control and Prevention (CDC) advises against all water usage, which includes washing dishes, doing laundry, and washing hands.
You should also stay away from anything connected to an electrical outlet, as lightning can travel through the electrical system. This means avoiding the use of corded electronics and computers during the storm. Cordless and cellular phones are safe to use, provided they are not plugged into a charger connected to the wall outlet.
Areas to Avoid
Stay away from areas containing metal components that can conduct electricity, including:
- Windows and doors
- Porches
- Concrete floors or walls
The National Weather Service recommends waiting a minimum of 30 minutes after the last sound of thunder before resuming any activities that involve water or electricity. This waiting period is necessary because lightning can strike far from the center of a storm, and the danger persists even when the rain has stopped.