The presence of legionellae was investigated over 2 years in various types of water in Israel. Potable water, fish ponds, oxidation ponds and surface water were sampled on a monthly basis. Legionellae were not isolated during the cold months of the year (November to April), but were continually isolated during the rest of the year (May to October). Nineteen of 56 sources of water were found culture-positive for Legionella pneumophila serogroups 1, 2, 3, 4 and 6, L. bozemanii, L. israelensis and some nonspeciated Legionella. As irrigation water in Israel originates from the various types of water that we found to be culture-positive for Legionella, the public health implications of this finding were correlated with our previous seroepidemiological survey of irrigation workers.