For the chlorinate and fill method, the chlorinated water must stay in contact with the storage facility for how long before filling?

• A. 1 Hour
• B. 6 Hours
• C. 12 Hours
• D. 24 Hours

Answer: (B)

The key idea is to give chlorine enough time to contact all interior surfaces and the water itself so microbes are inactivated before the tank is put into service. After chlorinating the water in the storage facility, you hold it for a period that allows the chlorine to penetrate the tank and kill contaminants. About six hours provides reliable disinfection without delaying operations more than needed. Shorter times, like one hour, may not achieve full contact; longer times (twelve or twenty-four hours) aren’t typically required for this method and would slow things down.