Citation: Judeh, T.; Shahrour, I.; Comair, F. Smart Rainwater Harvesting for Sustainable Potable Water Supply in Arid and Semi-Arid Areas. Sustainability 2022, 14, 9271. https://doi.org/10.3390/su14159271 Academic Editor: Vasilis Kanakoudis Received: 13 June 2022 Accepted: 26 July 2022 Published: 28 July 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). sustainability Article Smart Rainwater Harvesting for Sustainable Potable Water Supply in Arid and Semi-Arid Areas Tariq Judeh 1 , Isam Shahrour 1, * and Fadi Comair 2 1 Laboratoire de Génie Civil et géo-Environnement, Lille University, IMT Lille Douai, JUNIA Hauts-de-France, ULR 4515-LGCgE, F-59000 Lille, France; tariq.judeh.etu@univ-lille.fr 2 Energy, Environment and Water Research Center, The Cyprus Institute, Aglantzia 2121, Cyprus; f.comair@cyi.ac.cy * Correspondence: isam.shahrour@univ-lille.fr Abstract: This paper presents a smart rainwater harvesting (RWH) system to address water scarcity in Palestine. This system aims to improve the water harvesting capacity by using a shared harvesting system at the neighborhood level and digital technology. The presentation of this system is organized as follows: (i) identification of the challenges of the rainwater harvesting at the neighborhood level, (ii) design of the smart RWH system architecture that addresses the challenges identified in the first phase, (iii) realization of a simulation-based reliability analysis for the smart system performance. This methodology was applied to a residential neighborhood in the city of Jenin, Palestine. The main challenges of smart water harvesting included optimizing the shared tank capacity, and the smart control of the water quality and leakage. The smart RWH system architecture design is proposed to imply the crowdsourcing-based and automated-based smart chlorination unit to control and monitor fecal coliform and residual chlorine: screens, filters, and the first flush diverter address RWH turbidity. Water level sensors/meters, water flow sensors/meters, and water leak sensors help detect a water leak and water allocation. The potential time-based reliability (R e ) and volumetric reliability (R v ) for the smart RWH system can reach 38% and 41%, respectively. The implication of the smart RWH system with a dual water supply results in full reliability indices (100%). As a result, a zero potable water shortage could be reached for the dual water supply system, compared to 36% for the municipal water supply and 59% for the smart RWH system. Results show that the smart RWH system is efficient in addressing potable water security, especially when combined with a dual water supply system. Keywords: dual water supply; Palestine; rainwater harvesting; simulation; smart water; water scarcity 1. Introduction This paper introduces smart rainwater harvesting (RWH) and smart dual water supply systems to promote sustainable water security. RWH is an ancient practice that dates back to 2000 years BC [1]. It has been widely adopted in several countries worldwide includ- ing India [2], Sri Lanka [3], Kenya [4], Zambia [5], Ghana [6], Pakistan [7], Jordan [8,9], Afghanistan [10], Egypt [11], and Bangladesh [12]. The application of this paper targets water-scarce areas, such as the West Bank in Palestine. Such areas face severe environmental challenges [13], particularly a decrease in freshwater, population growth, and contamina- tion of water resources [14–19]. Moreover, conventional water supply systems have limited capacity to meet water demand [20]. For example, in the West Bank, conventional systems can provide only 60% of the domestic water demand [21]. In addition, scholars highlighted the vulnerability of the water system to contamination [19,22,23]. Several authors presented the advantages of using RWH [15,24–26]. Conventional rooftop RWH systems include a collection catchment, conveyance, and storage tanks [27]. Sustainability 2022, 14, 9271. https://doi.org/10.3390/su14159271 https://www.mdpi.com/journal/sustainability