Application of a water balance adapted to intermittent water supply and flat-rate tariffs without customer metering in Tiruvannamalai, India
Establishing the water balance developed by the International Water Association (IWA) is a worldwide applied approach to determine and analyse water losses in water distribution systems (WDS). The water balance covers those parts of a WDS within the responsibility of the water utility. Water losses occurring ‘before’ a customer meter are at the expense of the utility, while water lost or wasted ‘after’ the meter is paid for by the customer. This applies to systems where customer metering is in place and/or consumption is charged according to the consumed volumes. However, many WDS in the world lack customer meters, are operated intermittently and apply flat-rate tariffs. In intermittent supplies, a considerable amount of water is lost or wasted within the private properties. The flat-rate tariff might not cover this amount or part of the amount. Thus, actual consumption and wastage should be separately quantified with respect to the utility's water reduction measures. Accepting the described conditions, the authors have developed an adaption of the IWA water balance and the methods to establish the balance. In this paper the application of the developed approach in an initially unmetered WDS with intermittent water supply in the city of Tiruvannamalai, India, is presented.