This paper presents the approach Denver Water (DW) used to design a System Specific Study (SSS) to meet the Initial Distribution System Evaluation System Specific Study (IDSE) requirement of the proposed Stage 2 Disinfectants and Disinfection Byproducts Rule (Stage 2 DBP Rule). In early 2004, DW completed a three-phased project to develop an all pipes extended period simulation (EPS) distribution system model. The project's third phase was designed to enable the EPS model to assist DW preparations for meeting the IDSE requirement of the proposed Stage 2 DBP Rule. The model was hydraulically calibrated using traditional telemetry data and water age computations were verified through the use of a system wide fluoride tracer test. This model allows DW to better determine potential water quality sampling locations for Stage 2 monitoring than the Rule's proposed Standard Monitoring Plan (SMP). Field testing in late 2004 verified the model predicted an accurate correlation of THM formation by using distribution system residence times relative to the water treatment plant of origin. This paper presents the results of this initial study and some guidance to the DW operations staff for managing distribution system water quality and energy requirements. Includes figures.