Contamination of arsenic and fluoride in drinking water reservoirs is a serious health issue in the Sibi district, Balochistan, Pakistan. The contamination has already been affecting a large population of the district. Dental fluorosis and dermatitis are the most common reported illnesses in the area. This study focused on the evaluation of the root causes and pathway by which it reached to the body. Questioner analysis, simple examination, and pictorial representation were used to study the prevalence of diseases caused by As and F. People of the Sibi district were found to consume both surface and groundwater, which were highly contaminated with arsenic and fluoride. The saturation index, ranging from 1 to 7, showed high enrichment of contaminants in both types of water. Geochemical calculations and the sodium absorption ratio were evaluated. High values of the saturation index of different salts showed high saturation of salts in water. The principal component analysis grouped the data into three clusters, showing that the surface water has no resemblance with the control water. High degree of contamination was observed for most of the samples, whereas, some samples of ground water were closed to the control group; a group of samples within WHO limits. The correlation studies and other calculations also revealed that the F and As reached lethal limits in the drinking water and thus caused severe health damage to the local area population. The diseases found in the area are fluorosis, keratosis, dermatitis, and melanosis.