Besides air, water is the most important resource for humans. The availability of water and adequate sanitation are essential to protect children's health and their ability to learn in school. There is a close and interesting relationship between water supply and sanitation. Any school requiring adequate sanitation must have a stable water source. In this sense, we can consider water sources (like taps and wells) as examples of sanitary facilities. This may be in line with the WHO definition of sanitation, where it refers to the provision of facilities and services for the safe disposal of human urine and faeces. The availability of water is not a facility, but the structures (taps, wells, etc.) that enable the availability and accessibility of this resource can be called sanitation facilities. These facilities are essential for proper sanitation in any secondary school. The provision of these facilities guarantees accessibility to water and therefore quality sanitation. This therefore means that for proper disposal of human urine and feces, there must be water available and accessible. This simple fact defines the close relationship between water and sanitation. The concept of diminishing distance as highlighted by Getis et al, 2008 and the theory of location highlighted by Alfred Weber, 1929 can be used to explain the complex relationship between water and sanitation. – CONCEPT OF DECAYDistance Decay is the experimental decline of an activity, function or quantity of interaction with increasing distance from the point of origin (Getis et al 1998). This explains the fact that there is greater intensity (greater spatial interaction) in the use of facilities near the school zone, especially the distance between the water source and the school building. ..... middle of paper ...... links (especially those that make water available) and hygiene. Water is closely linked to quality sanitation, adequate education and gender equality. Girls who have to spend time fetching water for family use are unlikely to attend school. So, where schools have adequate sanitation facilities, girls' attendance is higher. Lack of adequate sanitation and private facilities has a greater impact on girls than boys, determining whether they ever go to school and also influencing how long they stay in school, as girls are more likely to enroll in school – and stay enrolled – when they graduate. measure of protection and respect. Understanding the complex relationship between water and sanitation using the concept of distance decay and location theory, then applying this knowledge will increase the number of girls in schools, especially in sub-Saharan Africa.