When disinfecting storage facilities using the surface application method, how long should the applied disinfection be in contact with all surfaces before portable water is introduced into the tank?

• A. 30 minutes
• B. 1 hour
• C. 2 hours
• D. 8 hours

Answer: (A)

Disinfection works best when the disinfectant stays in contact with all surfaces long enough to inactivate microorganisms. For the surface application method used in storing facilities, you apply the disinfectant to all interior surfaces and let it remain in contact for thirty minutes before introducing portable water. This minimum contact time ensures the agent has the opportunity to act across the entire surface area and achieve effective disinfection. After the thirty-minute contact period, proceed with the next steps to restore service. Longer contact times aren’t required for this method and would unnecessarily delay refilling.