Electrocution from lighting while showering or bathing is both scientifically possible and historically documented.
Bath-related deaths due to lightning are quite rare.
Lightning fatalities are a significant cause of weather-related deaths in the United States, killing an average of 49 people a year. Based on a review of lightning related fatalities from 2006 through 2013, the National Weather Service concluded that an overwhelming majority of those fatalities came from outdoor activities:
From 2006 through 2013, 261 people were struck and killed by lightning in the United States. Almost two thirds of the deaths occurred to people who had been enjoying outdoor leisure activities ... From 2006 to 2013, there were a total of 30 fishing deaths, 16 camping deaths, and 14 boating deaths, and 13 beach deaths. Of the sports activities, soccer saw the greatest number of deaths with 12, as compared to golf with 8. Around the home, yard work (including mowing the lawn) accounted for 12 fatalities. For work-related activities, ranching/farming topped the list with 14 deaths.
Implied in the above analysis is the conclusion that lightning strikes affecting people inside the safety of their home are relatively rare. Indeed, indoor lightning fatalities represent an ever-shrinking percentage of overall deaths, especially in the developed world. Still, this does not mean that indoor lightning fatalities are impossible, or that the mechanism of being injured or killed while taking a bath or a shower is impossible.
Lightning-struck ground near homes can send devastating jolts up pipes and into sinks and bathtubs, a phenomenon that can be compounded by the metal pipes used in household plumbing, which provides effective conduits for the massive electrical charges released by even a single bolt.
Such lightning-related injuries are relatively uncommon in the greater scheme of things because one has to be doing the dishes or bathing or showering in the right (or wrong) place at the precise moment when a bolt hits. However, people have occasionally been injured in this fashion:
- In May 2008, 15-year-old Falicity Wishkeno of Topeka, Kansas, was hit by lightning while taking a shower. Said Wishkeno, "Right when I got in the shower, I heard the thunder hit. I saw this big, white light. I jumped out of the bathtub and collapsed. I had trouble breathing, and I couldn't feel my legs at all. I felt all this pain in my legs and my whole body."
- In November 2007, a bolt struck a teenager who was washing her hair at her home in Blandford, England. Said Abbie Jackson of the event, "It hit my wrist and basically lit up my arm. The showerhead flew out of my hand."
- In October 2006, a woman in Croatia was struck by lightning while brushing her teeth just as lightning struck a pipe outside the her home. Said Natasha Timarovic of her experience, "I had just put my mouth under the tap to rinse away the toothpaste when the lightning must have struck the building. I don't remember much after that, but I was later told that the lightning had traveled down the water pipe and struck me on the mouth, passing through my body. It was incredibly painful, I felt it pass through my torso and then I don't remember much at all."
- In June 2001, Josephine Martine of Deal, England, was blown out of her bath tub by a lightning bolt. The mother of three, who had been soaking in her bath tub during a thunderstorm, was catapulted naked through the air by the force of the bolt, landing on the other side of her bathroom. Said Martine, "I felt a huge kick in my hand and knew straight away it was electricity. In a split second I saw the water rippling. The kick of the electric shock was so powerful I was sort of thrown out of the bath. It was scary, but it happened very quickly."
- In August 1988, as Eleanor Loux of Exeter, Rhode Island, brushed her teeth at her bathroom sink, she saw a bolt of lightning leap from her toilet. The resulting ball of fire then bounced off walls and the ceiling in her bathroom until it dissipated. Surprisingly, Loux was not injured. Her bathroom, however, was another story — the ceiling was cracked and the bathtub had charred rings in it. A utility pole outside her home had been hit by lightning, which sent the resulting charge through neighborhood power lines and metal water pipes.
In regards to how to remain safe indoors during a thunderstorm, experts advise:
A safe shelter is a building with electricity and/or plumbing or a metal-topped vehicle with windows closed. Picnic shelters, dugouts, small buildings without plumbing or electricity are not safe. There are three main ways lightning enters structures: a direct strike, through wires or pipes that extend outside the structure, and through the ground. Once in a structure, lightning can travel through the electrical, phone, plumbing, and radio/television reception systems. Lightning can also travel through any metal wires or bars in concrete walls or flooring.
- Stay off corded phones. You can use cellular or cordless phones.
- Don't touch electrical equipment such as computers, TVs, or cords. You can use remote controls safety.
- Avoid plumbing. Do not wash your hands, take a shower or wash dishes.
- Stay away from windows and doors that might have small leaks around the sides to let in lightning, and stay off porches.
- Do not lie on concrete floors or lean againt concrete walls.
- Protect your pets: Dog houses are not safe shelters. Dogs that are chained to trees or on metal runners are particularly vulnerable to lightning strikes.
- Protect your property: Lightning generates electric surges that can damage electronic equipment some distance from the actual strike. Typical surge protectors will not protect equipment from a lightning strike.
The long-standing warning that it is dangerous to take a bath or shower during a thunderstorm is indeed a scientifically factual and documented occurrence, but it is a demonstrably rare one. As such, we rate this claim a mixture.