This standard describes essential procedures for the disinfection of new and repaired potable water mains. New water mains shall be disinfected before they are placed in service. Water mains taken out of service for inspection, repair, or other activities that might lead to contamination of water shall be disinfected before they are returned to service. Major revisions made to the standard in this edition include the following: under Sec. 5.1.4 sample results, Heterotrophic Plate Counts greater than 500 colony forming units require additional flushing; Table 1 has been corrected; and, Ascorbic Acid was added in Appendix C as a neutralizing agent. An errata to this standard was published in June 2005 that corrects Sec. 4.4.3.3, Table 4 on P.11.