Microscopic bacteria, which are diverse and preponderant in all ecosystems, sense changes in any environment fast because of their ability to metabolize a variety of chemical substances for their nutrition and growth. In any environment loaded with toxic substances, bacteria would be low in number and diversity. When substrates are innocuous and easily degradable, bacteria are abundant and diverse. In this way, their responses to environmental changes are quick and consistent compared to higher forms of biota. Thus, bacteria as a community are useful and reliable indicators of ecosystem alterations. Through careful planning, choice, and analysis of relevant bacteriological parameters, deeper insights on quality, health, and stability of natural habitats are possible. In this paper, this is discussed in the context of water bodies in an area impacted by the tourism industry