Intensity, Duration, and Frequency of Residential Water Demands

Water demands at four single-family residences were monitored for a 1-yr period. About 8,000 demands per capita were recorded and converted to single equivalent rectangular pulses. Each pulse was classified by type (deterministic or random), location (indoor or outdoor) and day (weekday or weekend). Basic exploratory data analyses were performed to estimate sample statistics, cumulative distributions, and hourly occurrences of the intensity, duration, and volumes of the rectangular pulses according to type, location, and day. In addition, the hypothesis that residential water demands occur as a nonhomogeneous Poisson rectangular pulse process was examined. Results show that the simple rectangular pulse provided a very reasonable approximation of indoor water demands. However, the variance of the daily pulse count appears to be too high for a Poisson process. Potential causes of the high variances in the daily pulse count are discussed. Findings and data from this study can be used to develop and verify fine-resolution network models designed to predict the fate and travel time distribution of substances moving to remote points of consumption in the water distribution system.