Why must a boil order be issued when system pressure drops below a specified level?

Issuing a boil order when system pressure drops below a specified level is primarily a public health measure. When the water system experiences a loss of pressure, there is a risk that contaminants may be drawn into the water supply. This is particularly critical because the pressure drop can create backflow conditions, allowing bacteria and other harmful pathogens to enter the system.

The regulation under the Illinois Environmental Protection Agency (IEPA) emphasizes the importance of maintaining safe drinking water. When the pressure in the system is compromised, residents are advised to boil their water before consumption to eliminate any potential health risks. This action ensures that any possible microbial contamination is eradicated, thus protecting public health and safety. While compliance with laws, preventing equipment failures, and ensuring maintenance budgets are important aspects of water system management, the primary concern during a pressure drop is the protection of public health from waterborne illnesses.