The Clayton County (Georgia) Water Authority (CCWA) has installed ultraviolet (UV) disinfection systems at three water production plants (WPPs). The CCWA's projects were designed, constructed, and tested in advance of the publication of the Proposed Ultraviolet Disinfection Guidance Manual (UVDGM) by the U.S. Environmental Protection Agency (USEPA). On-site validation testing was successfully completed at the three facilities early in 2003. Following the June 2003 publication of the Proposed UVDGM, the UV system configuration and validation results for the CCWA's Freeman Road WPP were analyzed under the UVDGM framework. A comparison to the Tier 1 requirements indicated that not all criteria were met, so a Tier 2 analysis was necessary. From the Tier 2 analysis, the UV safety factors and dose requirement were reduced by approximately 12 percent compared to the proposed Tier 1 dose requirement. From these analyses, the CCWA systems exceed all potentially applicable USEPA requirements, and the CCWA is providing enhanced public health protection as intended upon project inception. As a result of these analyses, significant comments, focused on simplifying the UVDGM and enhancing its ease of use, were submitted to the USEPA. Includes 22 references, tables, figures.