At what pH level can the department immediately close a public pool?

The correct choice reflects that the pH level at which the department can immediately close a public pool is 7.2. Maintaining the proper pH level is crucial for both the effectiveness of chemical disinfection and swimmer comfort. A pH below 7.2 can lead to poor water quality, causing issues such as skin irritation and reduced efficiency of chlorine. At levels below 7.2, there are heightened risks for swimmer health, prompting regulatory authorities to take immediate action by closing the pool to ensure safety.

This standard is based on best practices and health regulations designed to protect public health, as pH levels outside the optimal range can compromise the quality of the water, making it potentially harmful for swimmers. Keeping the pH in balance is essential not only for sanitation but also for maintaining the overall integrity of the pool infrastructure.