Wound fiberglass depth cartridge filters (25.4 cm) with a nominal porosity of 1 μm were used to concentrate viruses from large volumes of surface water. They were found to be an excellent, less expensive alternative to the 0.2-μm pleated cartridge filters normally used for the concentration of enteric viruses from water. More than 99% of experimentally seeded poliovirus was adsorbed to these filters when the pH of the water was adjusted to pH 3.5 and aluminium chloride was added to a final concentration of 0.001 M, as recommended for electronegative filters. In comparative recovery of indigenous viruses from river water, similar results were obtained with two 1-μm or a 3-μm + 0.2-μm filter combination. The cost of the two 1-μm filters is about Can. $26, while it is about Can. $58 for the other combination.