This research letter reviews the recorded serum values obtained following the detection of perfluorooctanoic acid (PFOA) water contamination in Veneto, which are underestimations of the true extent of the internal contamination experienced by the exposed populations. The most likely peak serum concentrations were in a range with a median of 136.0 and an intequartile( IQR )of 64.8–258.3 ng/mL for young males and a median of 74.5 and an IQR of 22.6–167.4 ng/mL for young females, compared to the median serum PFOA contamination that was finally detected (64.1 for males and 30.2 ng/mL for females, respectively) when blood samples were drawn. This was 27 months after the implementation of the single granular activated carbon drinking water filtration and 30 months after the disclosure of the heavy drinking water contamination.