What must be done with a swimming pool enclosure gate when the pool is not in use?

The correct response indicates that the swimming pool enclosure gate must be locked when the pool is not in use. This practice is essential for ensuring safety and preventing unauthorized access to the pool area, especially in facilities such as nursing care institutions where vulnerable populations may be present. By locking the gate, it reduces the risk of accidents, such as drowning, and protects individuals, particularly children or those with cognitive impairments, from accessing the pool unsupervised.

While the other options suggest various forms of leaving the gate open or unsecured, these would fail to provide the necessary safety measures. Propping the gate open, keeping it ajar, or leaving it unlatched would all result in a lack of security, increasing the risk of accidents and liability for the facility. Thus, the requirement to keep the gate locked when the pool is not in use is not only a best practice but also often a legal requirement in many jurisdictions to promote safety and well-being.