Two methods based on virus adsorption and elution from glass powder were developed for the concentration of hepatitis A virus (HAV) from large volumes of water. The cytopathogenic pHM-175 strain of HAV was used to test these procedures in tap water, fresh water, sea water and raw sewage. HAV was quantitated by a plaque assay in the FRhK-4 cell line. HAV was concentrated by glass powder adsorption-elution from 20-liter samples with satisfactory efficiencies in all types of water: 100% for tap water, 80% for freshwater, 75% for sea water and 61% for sewage. The charge of glass powder was modified by polyethylenimine treatment to avoid the need to pretreat the sample. Concentration efficiencies of HAV in 20-1 samples through adsorption to and elution from positively-charged glass powder were 100% for tap water, 94% for sea water, and 61% for fresh water and sewage. Both methods were used for the detection of wild-type HAV in raw sewage. Wild-type HAV in concentrated sewage samples was detected by molecular hybridization with a digoxigenin-labelled cDNA probe.