This study focuses on quantitative and qualitative determinants of drinking water in the Tulkarem district of Palestine, and the effect of water pollution on the health of its inhabitants. Five hundred drinking water samples were obtained from the records of the Public Health Department/Ministry of Health (MoH) at Tulkarem district for the year 1999, which were collected from different sources in the district. The samples were examined for free chlorine residual concentration, total coliforms and faecal coliforms. Data of water-related diseases was obtained from the records of public health clinics in the district. Many of the examined samples were unacceptable according to the Palestinian and WHO standards. It was found that (60.6%) of the samples have concentrations of free chlorine residual less than 0.2 ppm, which is the minimum concentration, recommended by WHO. Out of these samples, 34% and 9.2% were contaminated with total coliforms and faecal coliforms respectively. It was obvious that the prevalence of water-related diseases is much higher in the areas with contaminated or nonchlorinated drinking water than in other areas.