We utilize a Generalized Exact Affine Stone Index system to evaluate the structure of residential water demand that recognizes demand interrelationship between residential and bottled water in the United States, allowing for precommitted consumption. Further, we address expenditure and price endogeneity by accounting for the supply side of the price determination mechanism. A significant substitutability relationship between residential and bottled water is found, while substantial precommitments are established in both residential and bottled water consumption. Residential demand becomes price-elastic once the precommitted level is reached. Finally, ignoring substitutability, precommitments, or endogeneity distorts the demand structure, resulting in erroneous policy implications.

This paper considers a model of household demand for water in a theoretical framework consistent with fundamental principles of consumer behaviour. It applies this model to individual household data to estimate the price and income elasticities of residential demand for water in Cyprus and evaluate the welfare effects associated with changes in the water pricing system. We find that the current regionally heterogeneous, increasing block-pricing system introduces gross price distortions that are not justified on efficiency grounds. A shift towards uniform marginal cost pricing will eliminate the deadweight loss of the current system. However, its benefits will be distributed in favour of the better-off households.