Rapid enumeration methods based on the enzymatic hydrolysis of 4-methylumbelliferyl-beta-d-galactoside and 4-methylumbelliferyl-beta-d-glucuronide were optimized for freshwaters. The enzymes beta-d-galactosidase (GALase) and beta-d-glucuronidase (GLUase) were shown to be already induced in freshwaters when tested, respectively, with the inducers isopropyl-beta-d-thiogalactopyranoside and methyl-beta-d-glucuronide. Both enzymatic activities were compared, respectively, with plate counts of total and faecal coliforms in freshwaters. Enzymatic methods and reference plate counts were significantly correlated in log-log plots. Moreover, the GLUase method allowed the detection of viable (presenting a detectable GLUase activity) but nonculturable Escherichia coli.