[Recent studies on the recolonization of drinking water]

About the re- or aftergrowth in drinking water there are some reports. But there are still no real ideas about the reasons and the colony counts to which the water may rise under practical conditions when there is no external influence. In these investigations drinking water was stored in a reservoir for 3-6 weeks and the increase of colonies was observed. In all six tests there was an increase in the colony count. The maximum counts fluctuated between 8-2000 colonies/ml. The water, a mixture of surface- and groundwater, had not a homogeneous tendency of re- or aftergrowth. The chemical parameters gave no indications to these differences.