New York City is in the design phase for the Catskill and Delaware ultraviolet (UV) disinfection facility, in collaboration with the Joint Venture (JV) of Hazen and Sawyer and CDM. At approximately 2- bgd, this will be the world's largest UV disinfection facility for drinking water. Validation based upon the US Environmental Protection Agency's (USEPA) UV Draft Guidance Manual will be conducted by HydroQual, Inc. (HQI) at the UV Validation and Research Center of New York (UVVRCNY), Johnstown, NY, with oversight by the JV and the New York City Department of Environmental Protection (NYCDEP). Other validation testing has been conducted at the facility and has resulted in data quality in compliance with the UVDGM requirements. The functional structure of the UVVRCNY is discussed. Data acquired at the UVVRCNY is used here to present some quality control and data uncertainty analyses that will be used during the NYC validation. Examples are provided for technical testing data, dose-response data, and flow-test data. Includes reference, tables, figures.