the aim of the present study was to research the relation between the isolated and identified pathogenic microorganisms in the water used in the milking, with the isolation and identification of the same in milk samples of teats showing clinical or subclinical mastitis. sixteen dairy farms were randomly chosen, in cerqueira cesar town - sp, which used mechanical milking. water of the farms was classified in relation to the presence of total and fecal coliforms such as in the standard or out of the standard of human potability. in the results obtained, 94% of the samples were classified as being out of the standards in relation to total and fecal coliforms. the identified microorganisms were escherichia coli (51%), enterobacter spp. (25%), enterobacter cloacae (8%), edwardsiella tarda (8%) and klebsiella oxytoca (8%). regarding the milk samples, 373 samples from suckling cows were analyzed, presenting clinical mastitis (n=19; 5%) and subclinical mastitis (n=354; 95%).animals presenting subclinical mastitis were identified by somatic cell count (scc), utilizing electronic equipment (somacount 300 - bentley), where the mean found was 1,631 x 103 cells/ml. the main identified microorganisms were staphylococcus aureus (30%), corynebacterium bovis (23%) and staphylococcus spp. (15%). according to the results obtained, coliform agents found in the water used in the milking were not present in the analysis of the milk samples of quarters presenting clinical or subclinical mastitis from the respective farms, showing that there was not an association between water quality and mastitis occurrence.