This study investigated the concentrations and congener profiles of polychlorinateddibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in intake sourcewater (source water) and tap drinking water (tap water) of drinking water treatment plants(DWTPs) measured from various locations in Taiwan. In order to have a better understandingon the influence of atmospheric PCDD/F deposition on drinking water, PCDD/Fs in theambient air of a DWTP (DWTP-LN) were measured and both dry and wet deposition on thewater treatment facilities were assessed. The results of this study indicated that the meanPCDD/F concentration in tap water (0.0037 pg I-TEQ/L) was found to be approximately 62%of magnitude less than that in source water (0.0097 pg I-TEQ/L). In addition, the totaldeposition flux (dry + wet) of PCDD/Fs entering the DWTP-LN was 27.0 ng I-TEQ/m2·yearand wet and dry deposition contributed approximately 12% and 88%, respectively. It revealsthat dry deposition is more important than wet deposition of PCDD/Fs in the ambient air ofDWTP-LN. Atmospheric deposition of PCDD/Fs will increase the level in source water ofDWTP-LN up to 8.91 × 10-3 pg I-TEQ/L, which is approximately 92% of the PCDD/Fs insource water. If a removal efficiency of 87% is achieved by conventional treatment processesincluding coagulation, flocculation, sedimentation and rapid sand filtration, the water aftertreatment may increase 1.16 × 10-3 pg I-TEQ/L, which is approximately 43% of theconcentration level in tap water. These results indicate that in the DWTP-LN, the influence ofatmospheric deposition of PCDD/Fs on the drinking water is of great significance, and water treatment facility with a cover is suggested.