Indigenous enteric virus removal from raw wastewater was examined in facultative and partially aerated treatment lagoon systems at paired sites in the southwest, southeast, and north central regions of the U.S. The virus samples were concentrated from large wastewater volume using the bentonite adsorption-elution technique and assayed by the plaque technique on BGM, HeLa and RD cells. Temporally related samples were collected from the influent wastewater and the effluent from the first and second pond in series in each system. In facultative lagoon systems, virus reductions of over 95 percent were observed as combined season averages. In all seasons, the greatest contribution to virus removal occurred in the first pond of each system. In partially aerated lagoon systems, effluent virus levels during the summer test period were comparable to those in the facultative systems. Also, in the aerated systems the greatest removal occurred in the second, or non-aerated, part of the system, characterized by longer retention times.