Which action is a direct step in treating a field water system?

• A. Potable water stored for use
• B. Water is heated for taste
• C. Disinfectant added
• D. Water is aerated

Answer: (C)

Disinfection is the direct action that makes field water safe by inactivating microorganisms as water is prepared for distribution. Adding a disinfectant, such as chlorine or chloramine, directly targets pathogens and reduces the risk of waterborne illness before it reaches users.

Storing potable water is about maintaining a supply rather than treating the water itself. Heating water for taste doesn’t reliably remove pathogens and wastes energy, so it isn’t a standard treatment step. Aeration can affect taste and remove some gases, and can aid in certain treatment goals, but it’s not the primary action used to ensure microbiological safety in a field water system.