States a major obstacle to gathering detailed data on the use of individual end-uses within residences and commercial buildings is the cost and complexity of the field tests. Presents a methodology which overcomes this problem by collecting highly-resolved hot water draw data (data averaged over 15 seconds). At this level of detail the flow patterns for individual end-uses within a residence can be identified. It thus becomes possible to disaggregate most of a home's hot water use into individual end-uses using only information on the flow of hot water from the water heater. Describes the application of the methodology to a single-family home and the laundry room of an apartment house. Presents and discusses the results.