Estimation of Water Demand Function for Urban Households: A Case Study in City of Marvedasht

• Main Authors: Seyed Nematolah Mousavi, Hamid Moahmmadi, Fardin Boostani
• Format: Article
• Language: English
• Published: Water and Wastewater Consulting Engineers Research Development 2010-06-01
• Series: آب و فاضلاب
• Subjects: Domestic Water; Demand function; Price Elasticity; Marvedasht
• Online Access: http://www.wwjournal.ir/article_1605_72dd157084ebc69cdad332041f599675.pdf

This study was carried out in city of Marvedasht, Fars Province, in 2007 to estimate the water demand functions, to determine the factors affecting water consumption, and to estimate household water consumption sensitivity to water pricing during different seasons of the year. Regression analysis and the TSP software were used for estimating the functions and the t-test was used to determine the significance of the parameters studied. The required data were obtained from 50 households using the stratified random sampling method and questionnaires. The factors investigated included income level, water price, size of household, average age and literacy, residence construction type and garden, number of bathrooms, number of cooling systems installed,  application of washing machine, number of automobiles, number of floors, and ownership. Based on the results obtained from the linear model, the independent variables used were capable of predicting 90.4, 84, 85.6, and 91.5% of the changes in water demand (the dependent variable) during the different seasons of spring, summer, autumn, and winter, respectively. Based on the estimated price elasticity, water demand falls by 11.6% for a 10% increase in water price. The independent variables used in the logarithmic method were capable of predicting 89, 85.5, 87.5 and 89.9% of the changes in water demand during spring, summer, autumn, and winter, respectively. Price elasticity rates for spring, summer, autumn, and winter were estimated at -0.9, -0.86, -0.87 and -0.92, respectively. The independent variable used in this study were able to account for 89.2% of the variations in water demand over the whole period and water price elasticity for the sampled households was estimated at -0.88.