Hot water use accounts for the second largest portion of residential energy consumption in the U.S. but it is poorly understood. ASHRAE research developed a cost effective, unobtrusive, and accurate protocol for measuring and characterizing residential hot water use called the “temperature-based event inference” method. This method directly measures the change in end use pipe temperature in conjunction with the measured flow at the hot water tank to allocate domestic hot water draws. The report describes the methods, procedures, and results of applying the method to five residences and sets the groundwork for collecting more extensive data. Two technical papers presented at the 2002 Annual Meeting are also available (Vol. 108(2) #4595, HI-02-8-1). 1172-RP, Metering Residential Hot Water by End Use (Development of a Standard Protocol), was sponsored by TC 6.6, Service Water Heating. The principle investigator was Dale Tiller of the University of Nebraska - Lincoln.