These rules are being amended to clarify, and thus, achieve more consistent compliance with, cross-connection control requirements for public water systems (PWSs). Also, these rules are being amended to significantly reduce the overall regulatory burden of cross-connection control requirements on community water systems (CWSs) and their residential customers by: (1) allowing a dual check device to be used as backflow protection at service connections from CWSs to residential premises where there is any type of auxiliary or reclaimed water system; and (2) allowing biennial instead of annual testing of backflow preventer assemblies required at service connections from CWSs to residential premises. Furthermore, these rules are being amended to require large CWSs—i.e., CWSs serving more than 10,000 persons—to submit annual cross-connection control program reports using a brief new two-page form. This requirement will be a slight additional burden on large CWSs, but these annual reports will enable the Department to better ascertain the operational adequacy of large CWSs and to more efficiently conduct sanitary surveys of large CWSs.