Measuring the Impact of Water Supply Interruptions on Household Welfare

Water scarcity frequently leads to a need for rationing. The choice of an adequate rationing method should be based on the impact on consumer welfare that is produced by each rationing plan. Some rationing schemes, such as the frequently used supply interruption method, can be regarded as changes in the characteristics of the good (in this case, time availability) that do not modify the pre-set consumer budget. Under the standard theoretical restrictions on consumer behavior compensating or equivalent variations/surpluses cannot be used to identify the impacts of these methods on household welfare. In this paper, we propose a set of sufficient conditions with respect to the utility function that allows for the evaluation of the compensating or equivalent variations/surpluses associated with changes in goods’ quality, even if those goods are considered to be essential for consumers. We use these conditions to compare the welfare losses associated with the water supply cuts implemented in Seville (Spain) to those that would result if water was instead rationed using price changes.