# Towards Sustainable Water Use in Two University Student Residences: A Case Study
###### Abstract  
This research is focused on the water usage patterns in two student residences--one for male students (Residence I) and the other for female students (Residence II). Surveys and measurements of flushing cisterns, taps, and shower flows were conducted to understand water use behaviors. Scenario 1 proposed replacing washbasian and kitchen taps and installing flow reducers in showers, while Scenario 2 combined Scenario 1 with a rainwater harvesting system for recharging flush cisterns. Showers were found to be the most water-consuming devices, accounting for 4% and 61.41% of water consumption in Residences I and II, respectively, followed by kitchen taps (31.51% in Residence I and 11.52% in Residence II). The flushing cistern consumption was 7.02% in Residence I and 13.22% in Residence II. The implementation of Scenario 1 anticipates a 13% reduction in total water consumption in Residence I and a 10% reduction in Residence II. The reduction in hot water consumption would result in a decrease in annual electricity consumption by 27.8% and 23.06% in Residence I and II, respectively. With the implementation of Scenario 2, the total potential water savings for Residence I could increase to 19.98%, and for Residence II, it could rise to 23.17%. The proposed measures aim to enhance water sustainability in these buildings and can be replicated elsewhere. water efficiency; male residence; students' university residence; female residence; rainwater harvesting system (RWHS); water and electricity bill reduction  
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[PERSON], [PERSON], A. 39.6% in extreme drought [7]. Nevertheless, the mean daily water consumption in Portugal is estimated at 175 L per inhabitant. [8]. Buildings are among the highest consumers of potable water globally [9], affecting the urban water cycle and contributing to climate change. Indeed, water treatment processes, water delivery to consumers, and wastewater treatment use significant energy, contributing to increasing CO\({}_{2}\) emissions [10; 11]. It has been reported that public buildings are the most significant water consumers in cities, often leading to high levels of water waste [12; 13; 14]. One of the leading causes of this phenomenon is that users are not directly paying for water bills and are not personally motivated to reduce them because they are frequently unaware of the necessity of water conservation [15; 16; 17]. Higher education institutions are known to be significant consumers of water and energy [13; 17; 18; 19]. However, given their intellectual capital and influence, they have a unique opportunity to propose water management strategies and take the lead in implementing sustainable water use measures within their buildings, setting a powerful example for all sectors of society [17; 20; 21]. Nonetheless, there are various barriers to achieving sustainability, like those faced by other public buildings. These also include a lack of knowledge and interest within the academic community, limited time available for academics, resistance from staff towards new attitudes and procedures, and a lack of societal pressure [21]. Additionally, the diversity in water and energy end-uses makes analyzing water consumption and planning for water conservation challenging [17]. Despite the mentioned difficulties, research on water conservation in higher education institutions worldwide shows significant potential for water savings in various end-uses [10; 12; 13; 16; 17; 19; 21; 22; 23; 24]. Inadequate management of water consumption can have significant socioeconomic and environmental impacts in the cities where these institutions are located, particularly in smaller towns [25]. Therefore, it is essential to implement sustainability measures to mitigate the negative impacts of higher education institutions on the surrounding environment. Several authors have proposed alternative solutions for sustainable water use, particularly to address extreme climate scenarios.