A substantial number of water distribution systems (WDS) worldwide are operated as intermittent water supply (IWS) systems, delivering water to consumers in irregular and unreliable manners. The IWS consumers commonly adapt to flexible consumption behaviors characterized by storing the limited water available during shorter supply periods in intermediate storage facilities for subsequent usage during more extended nonsupply periods. Nevertheless, the impacts of such consumer behavior on the performance of IWS systems have not been adequately addressed. Toward this direction, this article presents a novel open-source Python-based simulation tool (EPyT-IWS) for WDS, virtually acting like an IWS modeling extension of EPANET 2.2. The applicability of EPyT-IWS was demonstrated by conducting hydraulic simulations of a typical WDS with representative IWS attributes. Different IWS operation cases were considered by varying the amount and consistency of the water availability to the consumers. EPyT-IWS outputs showed that domestic storing of water within underground tanks and subsequent pumping into overhead tanks allow consumers to cope with the intermittent water availability and suitably meet their demands. Besides the interval, the clock time of the water supply was predicted to influence IWS consumers’ ability to meet water demands.

In developing countries, most water distribution systems (WDS) are operated as intermittent water supply (IWS) systems. A significant share of them also delivers water to consumers in irregular and unreliable ways. To meet water demands under such inconsistent WDS operations, IWS consumers commonly adapt to flexible consumption behaviors characterized by storing the limited water available during shorter supply periods in intermediate storage facilities for subsequent usage during more extended non-supply periods. Towards accounting for this characteristic behavior in understanding the IWS behavior more realistically, this paper presented the development, functioning, and application of a novel open-source PYTHON-based simulation tool (EPyT-IWS) for WDS, virtually acting like an IWS modeling extension of EPANET 2.2. EPyT-IWS integrates EPANET 2.2 solver with an independent hydraulic solver to mimic the water withdrawal during supply periods, storage in intermediate storage facilities, and subsequent use. The applicability of the simulation tool was demonstrated by performing extended-period hydraulic simulations on a typical WDS with representative IWS attributes. The simulation outcomes showed that practicing the typical consumption behavior, involving storing water within underground tanks and later pumping it into overhead tanks, allows consumers to cope with the intermittent water availability and meet their demands very suitably. Besides the water supply duration, the clock time of water supply in IWS systems was predicted to influence consumers' ability to fill the intermediate storage tanks and meet water demands. This study's overall findings can advance the state-of-the-art for planning, designing, and operating WDS with IWS characteristics.