Water samples were collected in accordance with the treatment process flow of the DWTP with the aim of validating the removal efficiency for each process separately. Water samples were collected weekly during the study period from the point directly before the raw water intake at the DWTP (11 samples), after CS, (11 samples), and after RSF (10 samples). The volumes of the samples collected were 0.5–1 L for raw water, 20 L for samples after CS, and 127–450 L for samples after RSF. The sample volumes varied based on the water quality and whether significant clogging inhibited the performance of the membrane filter. For example, larger sample volumes of raw water could not be filtered in this study due to high turbidity levels causing clogging of the filter. While this can be ameliorated by pre-filtering, the use of pre-filters can also inadvertently bind and reduce virus concentrations, and therefore this was not used in this study. The concentration of viruses for the RSF samples was performed on-site at the DWTP, while other collected samples were preserved in a cooler container with ice packs and transported to the laboratory, where they were refrigerated at 4 °C until further analysis