Grammatical improvements are made throughout the rule. Substantive changes are primarily made to general disinfection and chlorination requirements, which are revised to replace overly general requirements with specific requirements. Section R309-520-7 is revised to group similar requirements together. In Sections R309-520-6 and R309-520-7, titles are revised to more accurately reflect the contents of subsections. Also in Sections R309-520-6 and R309-520-7, previously un-numbered sections are numbered so that references to specific requirements can easily be made. Subsection R309-520-6(1) is rewritten to focus on ground water sources that don�t meet microbiological standards but are not affected by surface water intrusion. Subsection R309-520-6(3) is re-titled to reflect an emphasis on required disinfection of ground water and surface water sources. Subsection R309-520-6(4) is re-titled and rewritten to focus on the application point of disinfectants and achieving disinfection CT (disinfection concentration and contact time). Section R309-520-7 is revised by moving general disinfection requirements that apply to all forms of disinfection, not simply to chlorination, to Section R309-520-6 which covers general disinfection requirements. Section R309-520-7 is revised throughout to remove references to calcium and sodium hypochlorite because of the availability of new hypochlorite compounds not based on calcium or sodium. Subsection R309-520-7(2) is revised to clearly distinguish which requirements apply to chlorine gas supplied by small 150-pound cylinders and which apply to large one-ton cylinders, including requirements for the installation of gas scrubbers and separate ventilation systems. Subsection R309-520-7(3) is revised to distinguish between requirements that apply to handling bulk hypochlorite solutions and those that apply to handling small quantities. Degradation of hypochlorite solutions and the consideration of water quality when selecting hypochlorite tablets are also addressed.