Turns out, mom was right about this one.
There are some things in life that you’ve heard about a million times without even thinking to question their validity—like when mom told you you absolutely cannot shower during a thunderstorm. When you were younger, that was probably totally fine by you (an excuse to get out of a bath!), but now, it seems like a major inconvenience.
So what’s the deal with the claim that you can’t take a shower or bath during a thunderstorm? Turns out, there’s a real risk to your health there—but it’s a little more complicated than you might think. Here’s what to know about why you should skip shower time if there’s a thunderstorm going on outside—and what you can do instead.
So, thunderstorms are dangerous largely due to the lightning they produce (thunder and lightning come together, but lightning poses the bigger threat). Lightning is basically a giant spark of electricity in the atmosphere between clouds, the air, or the ground, according to National Oceanic and Atmospheric Administration (NOAA). Most lightning flashes made by storms start within a cloud and, if it’s going to strike the ground, a channel of energy develops downward toward the surface. When the lightning gets a hundred yards or so off the ground, objects like trees and bushes and buildings start sending up (invisible) energy sparks to meet it, NOAA explains. When one of those sparks connects with the downward developing channel, a huge electric current surges rapidly down the channel and you get a ground surge.
Here’s where your health comes into play: Lightning can affect people in a number of ways, either from a direct strike (when you’re directly hit by lightning, which is often fatal), a contact injury (where lightning hits something you’re touching), or a ground current (when lighting strikes the ground, and the ground current passes from the strike point, through the ground, and into you), according to the Centers for Disease Control and Prevention (CDC). About 10% of people struck by lightning die, usually from a heart attack, the CDC says. You can also get serious injuries like blunt trauma, neurological syndromes, muscle injuries, eye injuries, skin lesions, and burns.
Scary fact: Lightning can travel through your pipes and strike you while you’re showering. “The plumbing and other metal in our homes can serve as a conduit for electrical current,” Jeffrey A. Andresen, PhD, professor of geography, environment, and spatial sciences at Michigan State University, tells Health. “If you are extremely unlucky and in contact with some of the plumbing or other metal in your home and lightning strikes, you could be seriously injured or worse as electricity passes through the metal.”
But it’s not just the metal that’s an issue: Water can carry electrical currents from lightning, too, lightning expert Mary Ann Cooper, MD, professor emerita of emergency medicine at the University of Illinois at Chicago, tells Health. So, basically, showering in a thunderstorm leaves you open to a double-whammy of electricity that can travel through your pipes and the water in it to shock you while you’re just trying to clean up.
Why does this all happen? The lightning is trying to find a path to the ground, Jeffrey Peters, severe weather program coordinatorand lightning safety expert at NOAA, tells Health. “If lightning strikes a home directly or enters the building through the wiring, plumbing, or landline phone wire, the electricity will follow a path of least resistance through the wires or plumbing to reach the ground,” he says—and sometimes you can get in the way of that path.
Getting injured from showering during a thunderstorm is not something that happens a lot, but it can. “Is it common? No, but it is possible,” says Cooper. “There are no absolute safety guarantees except by complete avoidance.” Joseph Dwyer, PhD, a professor of physics at the University of New Hampshire, agrees. “It is possible for lightning to kill someone taking a bath or shower, so the smart choice is not to risk it,” he says.
Again, this is rare but it could happen. “I’ve been an ER physician for 13 years, and I have not seen someone struck by lightning in their house,” Nicholas Kman, MD, an emergency medicine physician at the Ohio State University Wexner Medical Center, tells Health. Still, he says, you’re making a risk-benefit analysis where you have something minor like getting clean on one end and the possibility of serious injury or death on the other.
If you did happen to shower during a thunderstorm and lightning struck, you could be at risk of passing out, getting burns from the heat of the water, numbness and tingling, having your heart stop, or even dying, Kman says.
It’s also important to remember these risks aren’t specific to showers or baths during a thunderstorm—you really have to stay away from anything that has to do with pipes when you see lightning or hear thunder outside. “People need to stay away from all plumbing in their home during a thunderstorm,” Peters says. “This includes not taking or doing the following: A shower, bath, washing your hair at the sink, or a sponge bath.” Dwyer says you should even avoid washing your hands or doing the dishes during a thunderstorm. If you absolutely have to clean yourself, it’s best to wipe down with a bathing or makeup wipe, or using a splash of water from a water bottle.
The rule: If you hear thunder in the distance, don’t try to rush to get a quick shower in. “If you can hear thunder, then you are close enough to the storm to have lightning reach your location, even though it may not be raining at your home,” Peters says. “Lightning can strike up to three to 10 or more miles away from the parent storm.”
Experts generally recommend waiting for 30 minutes after you last hear thunder before taking a shower or bath, just to be safe. “Sometimes thunderstorms can save up a big one for the end, and so you don’t want to be part of that grand finale,” Dwyer says.