The records of influents concentration for both BOD5 and TSS of Maamera sewage treatment plant which were chosen of this study are very important parameters, They play an important part in the planing and management of the national water resources. Most of these records have periods of missing data of the influent BOD5 and TSS. In this study a model for generating missing monthly concentrations influent BOD5 and TSS. Data are introduced. Initially univariate models using the Box-Jenkins approach were fitted to the logarithmically transformed series. Both transformed series were found to be generated by a random process using sampling theory were considered to be white noise. Ordinary regression analysis was performed. No significant correlation between influent BOD5 and TSS concentration were found.