system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
The minimum recommended concentration of free chlorine in drinking water at the end of one hour (mg/L) is -
assistant
The correct answer is  The minimum recommended amount of residual chlorine is 0.5 mg/L. Park's Textbook of Preventive and Social Medicine, 25th edition, Page No. 774