CHAPTER ONE
1.0    INTRODUCTION
Water is indispensable and intricately connected to life, without which there is no life. This is the reason for which water must be given the necessary attention at all times. Good drinking water is not a luxury; it is one of the most essential amenities of life itself. The supply of safe drinking water to all has therefore engaged the attention of many individuals, groups, governmental organizations and private organizations. (Adetunde et al. 2010).
 Drinking water free of pathogenic organisms is fundamental to breaking one of the principal transmission routes of infectious disease. This fact has stimulated worldwide investment in the construction of water systems that are designed to meet stringent water quality standards. (Trevett, 2004).
 Waterborne pathogens, including a variety of viral, bacterial, algal and protozoan agents, account for much of the estimated 4 billion cases and 2.5 million deaths from endemic diarrheal disease each year. (Kosek et al. 2003).
 Increase in human population has exerted an enormous pressure on the provision of safe drinking water, especially in developing countries (Umeh et al. 2005). Unsafe water is a global public health threat, placing persons at risk for a host of diarrheal and other disease as well as chemical intoxication (Hughes et al. 2005). Unsanitary water particularly has devastating effects on young children in developing world. Each year, more than 2 million persons, mostly children less than 5 years of age, die of diarrheal disease (Kosek et al. 2003; Parashar et al. 2003).
 Nearly 90% of diarrheal-related deaths have been attributed to unsafe or inadequate-water supplies and sanitation conditions affecting a large part of the world’s population (Hughes et al. 2005; WHO 2004). An estimated 2.6 billion persons lack access to adequate sanitation (Okonko et al. 2008).
The University of Benin, Benin City, has 5 main halls of residence (halls 1, 2, 3, 4 and 5). There are also various staff quarters in the school: Junior Staff Quarter, Senior Staff Quarter, Dentistry Quarter and Doctor’s Quarter. These halls depend on borehole water stored in overhead tanks for their water supply.
1.1    AIM OF THE STUDY:
 This study is aimed at the bacteriological analysis of the water from these tanks.
1.2    OBJECTIVES OF THE STUDY:
To attain the total bacterial count of the water samples.
To determine the coliform counts (Most Probable Number) of the water samples.
To determine the species of bacteria present in the water.