This article summarizes the results presented in US Environmental Protection Agency's (USEPA) report "Ultraviolet Light Disinfection Technology in Drinking Water Application -- An Overview," which was first published in 1996. The report describes one disinfection technique that may be used to meet the proposed Ground Water Disinfection Rule (GWDR). The final GWDR is to be issued by November 2000, as required by the 1996 Safe Drinking Water Act (SDWA). Availability, operational characteristics, and economic considerations have been central in the early phases of GWDR treatment evaluation at USEPA. This article, which follows the format of the USEPA report, provides background information and assesses UV light efficacy; UV viability, and maintenance; describes case studies; and evaluates, in a preliminary fashion, the costs of UV treatment. Includes 27 references, tables, figures.