Water, sanitation, housing and hygienic behavior plays dominant role in the transmission and intensification of diseases. To optimize utilization of limited financial resources, it is important to prioritize disease intervention methods in order to minimize mortality and morbidity cases. Realization of the environmental health components that respond to the practical effects of their contribution to transmission of diseases has greater chances of enhancing health at minimum cost. Data of frequency of diseases and mortality rate were collected from four municipal hospitals from districts of Ilala, Kinondoni, Temeke and Kibaha in Dar es Salaam and Coast Regions. The populations at risk were sub-categorized in relation to age; below five years and above five years. The age parameter assists on envisaging the major causes to be either in-house or in public domain. Data were analyzed to assess the role of water quality, water quantity, excreta disposal, waste disposal and hygienic education on spreading the diseases in order to come up with scientifically evaluated information. Scores were given to each intervention method depending on its important in controlling a particular disease in order to establish the role of each alternative on transmission of diseases and the relative importance of each component. The results indicate that incidences of malaria, skin and eye infections, pneumonia and diarrhea are frequent in these districts. Children under 5 years are particularly affected by pneumonia and diarrhea than adults. Malaria, tuberculosis and pneumonia are the major causes of mortality rates in these districts. Fatality cases are caused largely by malaria, pneumonia and diarrhea for children less than 5 years, but malaria, tuberculosis and pneumonia are responsible for mortality rates in adults and children over 5 years. Statistical analysis revealed that in all districts, hygiene education is the major factor responsible for transmission of diseases accounting for 32~39%. Other factors, which are the major contributors to the incidences of diseases, are inadequacy of water (15.6~22.5%) and poor housing environment (14.5%~24%). Water quantity played the least role in transmission of diseases accounting for only (3~8%).