Indoor Pools and Lightning

Florida Couple's Toilet Explodes As Lightning Strikes Near Septic Tank:  'Proof Why You Shouldn't Go Near the Bathroom in a Thunderstorm'

It is spring in Texas and that means thunderstorms. It may appear logical that pools and lightning don’t mix, and that is certainly true for outdoor pools. But what about indoor pools? The magazine Aquatics International ran an article in their January 2008 issue entitled “When Lightning Strikes” written by Tom Griffiths and Matthew Griffith. They argued that the practice of clearing indoor pools during outside thunderstorms does not keep people safe and in many cases, may put them in higher-risk situations.

First they looked at statistics from 1990-2003. During that time no deaths were recorded from lightning during indoor swimming activities. There had been 60 swimming pool electrocutions during that time but none of them were from lightning. The reason for that is that the National Electric Code, which has been adopted by every governmental body in the United States, requires all buildings to have the ability to shunt the voltage generated by a lightning strike. What that means is that a building must have a complete lightning protection system, and be properly grounded and bonded. Any indoor pool that is up to the required code is in violation of the National Electric Code section 250.4(A)(1) if they close during a thunderstorm.

The problem is that when the pool closes it puts swimmers and water fitness class participants at greater risk than if they had continued their pool activities. Typically they go to the locker rooms where they shower before changing. There have been numerous cases of shocks and electrocutions of people in showers, or at sinks washing their hands. Some swimmers will be children who have to call for a ride home. There are reports every year of people injured from being shocked while using a landline phone. People who leave the facility have to walk through the parking lot to get to their cars, exposing themselves to a direct lightning strike. In 2006, 99.5% of lightning-related fatalities occurred outdoors. Two occurred indoors, one to a teenager near a window and one to a person using a landline phone. Griffiths and Griffith refer to the idea that indoor pools should close during a thunderstorm as an “urban myth.”

In the June 2019 issue of Aquatics International, Shawn DeRosa followed up on the topic of lightning and indoor pools. He reported that researchers found that there continues to be no unanimity about whether to close an indoor pool during a thunderstorm. 62% of pools stay open. Of the facilities that required patrons to exit the pool, 43% allow patrons to use showers and sinks, and only 13% advised patrons to stay indoors.

Hopefully, your pool allows you to continue your water fitness class or your lap swimming or your swim lessons during a thunderstorm. It is the safest place for you to be. If your class ends or you finish your last lap, then exit the pool and dry off, but stay out of the showers and don’t wash your hands. Give your child a cell phone if he needs to call for a ride home. Then stay indoors, away from large windows or open doors until the storm passes. Stay safe!

See you in the pool!

Author/Instructor Photo

Chris Alexander