New York Associate Public Health Sanitarian Practice Test

Coliforms in surface water signal potential microbial contamination, so the priority is to protect people while you figure out what’s happening. The immediate action is to issue a boil-water advisory and start an investigation into contamination sources. A boil-water advisory instructs people to boil tap water before drinking, cooking, or brushing teeth, reducing the risk from pathogens that might be present even if disinfection is ongoing. Investigating sources helps identify how contamination entered the system—whether from sewage, runoff, or a treatment failure—and guides the corrective steps to restore safe water. While increasing chlorination can be part of the longer-term treatment plan, it isn’t the sole or guaranteed immediate remedy and may not promptly ensure safety. Evacuation and closing the utility are far more drastic actions reserved for acute, verified hazards beyond routine coliform findings.