What is the free chlorine level requirement for public pools?

The correct choice regarding the free chlorine level requirement for public pools is a standard that helps ensure the safety and health of swimmers. Public health guidelines typically specify a minimum free chlorine level of 1 ppm (parts per million) for effective disinfection. This level is sufficient to kill harmful pathogens, such as bacteria and viruses, while also preventing the spread of waterborne illnesses in a high-traffic environment like a public pool.

Maintaining this minimum concentration is critical for the overall sanitation of the pool water, as it helps to oxidize organic matter and maintain water clarity. Levels above this, while possibly more efficient at disinfection, can also lead to issues such as chlorine irritation for swimmers and chemical imbalances that could affect the pool's water quality.

While other levels mentioned, such as 0.5 ppm, may not provide adequate protection against pathogens, and higher levels like 2 ppm or 3 ppm may be used under certain conditions or for specific treatment protocols, 1 ppm remains the recommended minimum for routine public pool operation to balance safety and comfort.