Objective   To study the relationship between heterotrophic plate counts and some physical and chemical parameters.

  Methods   Detection was made on the parameters such as total chlorine, free chorine, turbidity, assimilable organic carbon(AOC)in a northern city distribution network of China.

  Results   HPC got from R2A medium with longer culture time could reflect the real situation of bacteria in drinking water well.Free chlorine had a good negative correlation with HPC.The results of turbidity had good positive correlation with HPC.It seemed that AOC content seems had no correlation with amount of heterotrophic bacteria.

  Conclusion   There are many parameters affecting biological water quality especially in the residential area with complex water power condition, it can't be represented by one parameter and it should be thought about with all parameters synthetically.