A reader wrote in to ask, “Is it safe to shower in a thunderstorm? Were my parents messing with me?”
Anahad O’Connor titled his 2007 book with a pretty clear warning, Never Shower in a Thunderstorm. Normally, if lightning hits a house or other building, its inhabitants are pretty well protected. Electricity follows the path of least resistance to the ground and will travel through a good electrical conductor over a bad one, given the option. Metal framing, ductwork and plumbing all make better conductors than a human does, so the electricity from a lightning strike would get conducted through one of those things and then dissipate into the ground.
Take a shower or a bath or even start washing a load of dishes at the kitchen sink, though, and you open up the possibility that, given the option, you might be the better conductor for electricity to flow through. Metal is a good conductor and, like we already said, electricity from lightning strikes can and does flow through buildings’ metal pipes. The water flowing through these pipes—as nice as your local tap water might be—also contains impurities that help conduct the current. What’s more, your body’s resistance to electricity is cut significantly when you’re wet. If lightning strikes while you’re in contact with a pipe or faucet or water flowing through it, it’s possible that the current might find its way to you, and that won’t be pleasant.
Possible, though not probable—your odds of being struck by lightning in any fashion in a given year are 1 in 775,000, according to the National Weather Service. Still, you don’t want to end up like Josephine Martine, a UK woman who was “catapulted” from her tub and clear across the bathroom after lightning traveled through the pipes and into the shower head she was touching.