If a water treatment process fails, the initial action to take is to:

The initial action in the event of a water treatment process failure should prioritize public safety and compliance with regulations. Notifying local health authorities ensures that appropriate measures can be taken to protect public health. Authorities often have protocols in place to assess the situation and manage potential health risks associated with compromised water quality. This step is crucial for effective communication and swift action to safeguard the community.

While options like checking dye tests or consulting the plant operation manual are important steps to diagnose the problem, they come after ensuring that the health and safety of the public is the foremost priority. Stopping all treatment activities could be seen as extreme and might not be necessary if the issue can be addressed in a way that does not immediately endanger public safety. Therefore, the correct approach begins with alerting local health authorities to facilitate an appropriate response.