[Objective] The water quality and health hazards regarding heavy metals in drinking water sources in rich ore karst areas were studied in order to improve environmental control measures of water sources, thereby providing a theoretical basis for local drinking water health risk management and a reference for controlling and preventing accumulations of heavy metals in water. [Methods] Drinking water sources in Bijiang District, Tongren City, Guizhou Province were taken as an example. Conventional water quality indicators and the content of heavy metals (Fe, Mn, Cu, Zn, As, and Pb) were monitored from January 2018 to June 2020. In addition, a water quality fuzzy evaluation was carried out by using the relative membership degree and grade eigenvalue, and the single entropy weight method with the clustering weight method. The content characteristics of heavy metals and health risks in wet and dry seasons were evaluated by using the health risk assessment model recommended by the U.S. EPA. [Results] Water quality of drinking water source areas had reached class Ⅲ of improved fuzzy synthetic evaluation. The main excess factors were total nitrogen and total coliforms. The maximum values of Fe and Pb in the surface water sources had exceeded the class Ⅲ water standards. Fe, Zn, and Pb mainly came from mining and industry, Mn and As mainly came from agriculture, and Cu mainly came from agriculture and traffic pollution. [Conclusion] The water quality evaluation results based on the combined weight and optimization of fuzzy synthetic evaluation were more credible and reasonable than the conventional model with a single weight. The carcinogenic heavy metal As was the main element causing health risks. Children are more susceptible to heavy metal hazards than adults. It is necessary to strengthen control and governance of health risks from heavy metals.