As part of AwwaRF Project 3117, "Development of a UV Disinfection Knowledge Base", the first of eight UV facility site visits was conducted at Poughkeepsie's water treatment facility in Poughkeepsie, NY during December 11-15, 2006. The objectives for the one-week visit, as defined in the AwwaRF project scope of work, included: evaluate on-line UVT monitor function and comparison with bench-top Hach DR4000 UV spectrophotometer; evaluate sensor-to-sensor variability of duty and reference UV sensors; evaluate on-site laboratory UV spectrophotometers with NIST traceable wavelength standards and a recently calibrated HACH DR4000; evaluate lamp aging, quartz sleeve fouling and sensor fouling; evaluate power consumption as a function of ballast power setting; characterize S/So relation as a function of ballast power setting and UVT using a clean reactor with new lamps and quartz sleeves; identify new and used lamps and quartz sleeves for evaluation by Alexander Cabaj; and, evaluate mercury release issues. Issues of particular interest to plant operations staff included difficulty with "wet" sensors in performing reference/duty sensor checks. Each reactor requires draining before sensors can be switched. Plant staff suspects that the length of time required to drain and fill reactors may be affecting the accuracy of the reference and duty sensor comparisons due to drift in UVT and lamp operating temperature. Due to the length of time required to make reference sensor checks, it is only possible to use one reference sensor for each duty sensor position. Another issue of particular interest to plant operations staff was that recent reporting requirements stipulate that the measurement agreement between the on-line and laboratory UVT monitors should be within two percent. This is not always possible and staff is concerned about being out of compliance with this requirement. One week prior to the site visit, all test equipment necessary to conduct on-site testing was shipped to Poughkeepsie, NY. The test equipment included: computer based instrumentation package including a digital oscilloscope to measure UV sensor characteristics; reference UV sensor and dry sensor port retrofit; portable UV optics test bench used to measure quartz sleeve fouling; reference radiometer used with the optics test bench; five gallons of LSA for UVT adjustment; chemical feed pump to feed LSA into the reactor flow; and, Fluke Model 434 three-phase power quality analyzer. Includes tables, figures.