This review examines the rate constants for hydrolysis in water of 12 classes of organic compounds with the objective of using these data to estimate the persistence of these compounds in freshwater acquatic systems. Primary data were obtained by literature review through most of 1975 and some of 1976. These data, which include values for acid, base, and water promoted rate constants (kA,kB,kN) and temperature coefficients are presented in 18 tables in section 4. Estimated rate constants for hydrolysis under environmental conditions are presented in 13 tables in section 5, including rate constants at 298 K and pH 7 for acid, base, and water promoted reactions together with values for the estimated rate constant (kh) and the half‐life (t1/2).