A strike poses an immediate and serious risk to anyone in or near the water. The common perception that water is safe because it is “not pure” is misleading when dealing with the immense power of lightning. The electrical charge can spread rapidly through the pool, making the area extremely hazardous.
The Physics of Lightning and Water
Lightning is a massive discharge of electricity that seeks the path of least resistance to the ground. While chemically pure water is a poor conductor, pool water contains dissolved minerals, salts, and chemicals that allow it to conduct electricity efficiently enough to be lethal. A direct strike to the water surface instantly electrifies the entire pool volume.
The danger extends far beyond a direct hit because of ground current. A strike to the concrete deck, a nearby tree, or the surrounding yard can send a deadly electrical charge through the ground. This phenomenon, often called step potential, means the current travels through the earth and into the pool’s water and metal components.
The concrete pool deck, especially when wet, also becomes a conductive surface. Anyone standing on the wet ground near the pool during a strike is at risk of electrocution as the charge travels through the surrounding environment. Standing near the edge of the pool during a storm is unsafe.
Immediate Safety Protocols
Safety during a storm relies on immediate and decisive action. The standard rule of “when thunder roars, go indoors” applies emphatically to pool areas. As soon as thunder is heard, or lightning is seen, everyone must immediately evacuate the water.
Lightning can travel horizontally for several miles, and its strikes are unpredictable, making shelter a necessity. Seeking refuge requires moving to a substantial, enclosed building, such as a house or community center. Small, open structures like gazebos, shade umbrellas, or isolated trees do not offer adequate protection and should be avoided.
Do not resume swimming or being near the pool area until a minimum of 30 minutes has passed since the last sighting of lightning or the last sound of thunder. This waiting period ensures that the immediate risk from the storm cell has passed and allows any residual electrical charge to dissipate safely.
Potential Damage to Pool Equipment
Beyond the immediate danger to people, a lightning strike, whether direct or nearby, can cause extensive damage to pool infrastructure. The massive electrical surge often travels through the surrounding electrical and plumbing lines. Low-voltage electronics and sensitive circuit boards are vulnerable to these power spikes.
Expensive pool components are frequently damaged, including variable-speed pumps, digital automation systems, and salt chlorine generators. Heaters, particularly electric or gas models that rely on sophisticated circuit boards, can be instantly rendered inoperable. Even the wiring for underwater lighting systems can be compromised by a surge.
The surge can also travel through the metal components of the pool’s bonding system, potentially causing structural damage. This energy can lead to cracking in the concrete or decking near the entry points of the electrical lines. Repairing or replacing these components often requires significant time and expense.
Long-Term Protection Measures
Pool owners can take proactive steps to mitigate the financial risk associated with lightning-induced equipment failure. The most effective defense against electrical surges is the installation of surge protection devices. These devices divert excess voltage safely into the ground before it reaches sensitive equipment.
It is recommended to install a whole-house surge protector at the main service panel, which offers broad protection for all connected electronics. Additionally, a dedicated sub-panel surge protector specifically for the pool equipment pad provides a secondary layer of defense for the most vulnerable components. These devices act within nanoseconds to shunt the harmful energy.
Ensuring the pool’s grounding and bonding system is compliant with current electrical codes is paramount for long-term safety and protection. Bonding connects all metallic components—such as ladders, diving board bases, and pump motors—into a single electrical potential. This connection helps to equalize any stray electrical current, including a lightning surge, safely dissipating the energy into the ground.