Perfluoroalkyl acids (PFAAs) with carboxylic or sulfonic acid groups remain major pollutants in drinking water, posing a significant health risk. To explore the spatial and seasonal trends in PFAA exposure risks, considering different industrial layouts and water consumption habits, this study quantified 11 typical PFAAs in source and drinking water samples collected during winter and summer across nine major water basins in China. PFAA exposure and associated risk were evaluated based on age- and region-specific water consumption habits, and trends in source water contamination were analyzed in relation to varying production activity profiles. Drinking water has become the dominant source of PFAA exposure, mainly due to source water pollution from PFAA-related manufacturing and consumption. Exposure to PFAAs via drinking water varied among different water basins and seasons with total PFAA concentrations ranging from 0.0175 to 22.2 ng/kg/day. A greater risk of exposure to PFAAs was observed in populations from industrialized or highly urbanised areas in eastern and southern China, with a maximum health risk index of 5.53. C8 PFAAs, although regulated, remain the main risk component in drinking water, indicating these contaminants need to be revisited to enhance health-based drinking water safety management. Further studies on the establishment of health-based drinking water standards, water treatment technology updates, and source pollution reduction are required to control the risks of PFAA exposure in drinking water. This study provides important support for the global management of PFAA safety in drinking water.