Social & Preventive Medicine Which one of the following is the level of residual free chlorine recommended for swimming pool water disinfection? A 0.5 mg/litre B 0.8 mg/litre C 1 mg/litre D 5 mg/litre 💡 Explanation Which one of the following is the level of residual free chlorine recommended for swimming pool water disinfection? ✓ Correct Answer: C. 1 mg/litre