Structure and data requirements of an end-use model for residential water demand and return flow

An end-use model for residential water demand and return flow is presented in this paper. The model requires a unique description of a single residential stand in terms of all its end-uses. The end-uses include toilet flushing, bathing and showering, garden watering, pool water use, leaks, et cetera. Various parameters describe each of the end-uses. The model predicts five components relating to water use and wastewater flow at a residence: indoor water demand, outdoor water demand, hot water demand, wastewater flow volume and concentration of total dissolved solids in the wastewater. The large number of input parameters in an end-use model allow for powerful and detailed analysis of water demand. The various parameters required to populate the model are discussed, guideline values are presented and possible methods for calibration of the model to measured results are proposed. The model calculates 12 monthly results, for each of the five components, to provide a typical seasonal pattern as well as an annual value. WaterSA Vol.30 (3) 2004: 293-304