A little-known but serious hazard associated with hot tubs, known as suction entrapment, can trap bathers underwater by pinning them to the spa drain or suction outlet. This occurs when a person blocks the drain, which is connected to the hot tub’s filtration system and jets, creating powerful suction that can hold them in place and make it difficult or impossible to escape without assistance.

Matt Reynolds, a forensic engineer and aquatic safety specialist who investigates pool and hot tub accidents, identified three main types of suction entrapment. The first, hair entanglement, typically involves individuals with long hair, often teenage or adult females, whose hair becomes caught in the drain, pulling them underwater. The second type, body entrapment, occurs when a person’s torso creates a seal over the suction outlet, with the resulting suction force preventing them from breaking free unless the pump is turned off. The third type, finger entrapment, happens when a finger slips into a small hole or through a damaged drain cover and becomes stuck.

Such incidents can be difficult to resolve, as even those attempting rescues often struggle to free victims due to the strength of the suction. One of the most widely known cases involved Virginia Graeme Baker, a seven-year-old girl who died after becoming trapped by a spa drain in the United States. Her death prompted significant regulatory changes and the introduction of enhanced safety standards in the U.S., including improved drain covers and mandatory safety features designed to reduce the risk of entrapment.

However, safety regulations and standards vary considerably between countries, and the risk remains present in facilities that do not adhere to strict guidelines. Experts continue to urge caution and the adoption of preventative measures such as anti-entrapment drain covers, regular maintenance of spa equipment, and immediate pump shutoff mechanisms to mitigate the risk of suction injuries and fatalities.