When fecal coliform organisms are found in a water supply, it is an indication that:

The presence of fecal coliform organisms in a water supply is a significant indicator of potential contamination and health risks. Fecal coliform bacteria, such as E. coli, originate from the intestinal tracts of warm-blooded animals, including humans, and their detection often signifies that the water has been exposed to fecal matter. This raises concerns because it suggests not only that the water supply is contaminated but also that pathogenic organisms, which can cause diseases, may be present as well.

Additionally, the finding of fecal coliform implies that the overall quality of the water may be compromised, thus making it potentially unsuitable for drinking or other purposes. As such, the correct interpretation is that when fecal coliform is detected, it serves as a warning sign encompassing contamination, the possible presence of harmful pathogens, and the suitability of the water for consumption, leading to the conclusion that all of the provided statements collectively hold true.