What should be the first action taken if a well tests positive for coliform bacteria?

When a well tests positive for coliform bacteria, the primary concern is the safety of the water for human consumption. Coliform bacteria can be an indicator of fecal contamination, which poses significant health risks. The most appropriate action is to disinfect the well and subsequently retest the water to ensure that the disinfection process has effectively eliminated the bacterial contamination.

Disinfecting the well typically involves methods such as chlorination, which can kill bacteria present in the water and the well structure itself. After disinfection, retesting is crucial to confirm that coliform levels have returned to safe standards. This process ensures that the water is safe for use and provides reliable feedback on the effectiveness of the disinfection.

Ignoring the results could lead to serious health risks, and changing the water source or installing a filtration system may address the symptoms without tackling the root problem of contamination within the well itself. Therefore, disinfecting and retesting directly targets the concern at hand, making it the appropriate first action.