Potential Contamination Due to Cross-Connections and Backflow

In an answer to a question titled “A question about backflow” on the EPANET User-List Elin Warn gave a link to an article by the EPA:

The purpose of this document is to review existing literature, research,and information on the occurrence, magnitude, and nature of the public health risks associated with cross-connections and backflow, from both acute and chronic exposures, and methods for detecting and controlling the occurrence of cross-connections and backflow within distribution systems. More specifically,the goal of
this document is to review what we know regarding:
(1)causes of contamination through cross-connections;
(2)the magnitude of risk associated with cross-connections and backflow;
(3)costs of backflow contamination incidents;
(4)other problems associated with backflow incidents;
(5)suitable measures for preventing and correcting problems caused by cross-connections and backflow;
(6)possible indicators of a backflow incident;
(7)research opportunities.

See the full text here.