What is the required free residual chlorine level in a pool?

The required free residual chlorine level in a pool is greater than 0.5 mg/L because maintaining this level is essential for effective disinfection and sanitation. Free chlorine acts as a powerful oxidizing agent that helps kill harmful pathogens, such as bacteria and viruses, that can pose health risks to swimmers. A level above 0.5 mg/L ensures that there is sufficient chlorine present to actively break down contaminants and maintain water quality.

If levels fall below the recommended threshold, the pool may become unsafe for swimming due to the potential for pathogen survival and growth. It's also worth noting that while free chlorine levels can vary depending on local regulations and pool usage, the general consensus is that levels should be maintained above this minimum to ensure safety and health standards in aquatic facilities.