We accounted for capital, operation and maintenance, and energy costs. All costs were normalized to the economic indicator of USD•cap -1 •yr -1 . Specifically, capital cost covered all the purchases that the units required at start (e.g., housing for the UV systems, water storage bottles) while operation and maintenance accounted for cost estimates of all consumables materials and parts that require periodic replacements (e.g., NaClO, lamps, AgNP coating).