Evaluating mediums and plating techniques for enumerating bacteria in water distribution systems

Abstract

Two drinking water distribution systems, one containing chlorinated surface water, the other unchlorinated groundwater, were sampled bimonthly from June 1978 through September 1979 to evaluate mediums and plating techniques for bacterial enumeration. Both total and pigmented bacterial colonies were counted by using several different mediums at 20° C and 35° C incubation conditions with both the spread plate and pour plate methods. Results showed the pour plate method to be inferior to the spread plate method for the enumeration of total and pigmented bacteria in both distribution systems.