1. Introduction
Water, an indispensable resource for sustaining life, driving economic growth, and safeguarding environmental sustainability, stands out as one of the most critical natural resources due to its pivotal role in fostering prosperity and abundance. In fact, water is indispensable for human health and survival, being necessary for drinking, cooking, sanitation, and hygiene [
1]. Access to clean water is crucial for preventing diseases and maintaining overall health. Moreover, water is indispensable in agriculture and food security practices, including irrigation, livestock, and aquaculture. It guarantees sufficient crop yields and mitigates food shortages. Numerous industries depend on water for their production processes, cooling, and cleaning, emphasizing its crucial role in sectors like manufacturing, energy production, and mining. Additionally, water bodies such as rivers, lakes, and oceans sustain diverse ecosystems, offering vital services like climate regulation and habitats for various species, thereby promoting environmental sustainability and biodiversity [
1,
2]. However, in the 21st century, water scarcity and contamination emerge as predominant environmental obstacles on a global scale. According to the 2023 UNESCO’s report [
2], approximately 2 billion individuals, corresponding to 26% of the global population, do not have access to safe drinking water. In fact, the escalating demands on water resources worldwide, driven by economic growth and population expansion, and worsened by climate variability and climate change, are responsible for water scarcity.
With the demand for water on the rise and supplies limited, it becomes essential to prioritize sustainable water usage. This involves adopting water-saving technologies and practices in agriculture, industry, and households. To address these challenges, in 2015, the United Nations instituted 17 Sustainable Development Goals, commonly referred to as the Global Goals, through the 2030 Agenda for Sustainable Development. These goals are closely linked, with achievements in one goal impacting outcomes in the others. The 2030 Agenda emerged from collaborative endeavors involving governments and citizens worldwide, aiming to establish a fresh global framework to eradicate poverty, foster universal prosperity and well-being, safeguard the environment, and combat climate change [
3]. Specifically, Goal 6 is targeted towards guaranteeing both the access to and sustainable handling of water and sanitation. As outlined by the World Meteorological Organization, freshwater, in adequate volume and quality, is essential across all facets of life and to sustainable progress. Undoubtedly, access to clean drinking water and sanitation is fundamental to human dignity and is acknowledged by practically every nation. Water resources are intricately linked with every aspect of sustainable development, including ensuring food security, promoting health, and reducing poverty. Moreover, they play a crucial role in supporting economic development across agriculture, industry, and energy production, while also preserving the health of ecosystems [
4].
Agriculture utilizes around 70% of the water withdrawn from rivers, lakes, and aquifers [
5]. Intensifying agricultural practices leads to higher water consumption levels. Additionally, commercial sectors, industrial activities (especially in the food sector), and public water supplies also require substantial water use. Additionally, the pollution of both surface and groundwater resources must be taken into account [
6], as this issue is frequently attributed to agricultural and agro-industrial practices [
7]. Indeed, 25% of European groundwater is of low quality, primarily due to agricultural practices [
8]. Therefore, it is essential to recognize the importance of efficient water resource management, ensuring its quality and preventing both degradation and waste, to safeguard the future availability of water resources [
9]. Thus, safeguarding and sustainably using water is a key aspect of the United Nations Sustainable Development Goals, aiming to guarantee that everyone has access to water that meets high quality standards, i.e., water that is clean, uncontaminated, and responsibly managed [
3].
Motivation and Main Contribution
To implement effective water conservation policies that promote water-saving behaviors, it is essential to understand users’ awareness levels and consumption patterns. In this context, providing new insights into the population’s awareness of water issues and its attitude towards water resource conservation, as well as its awareness of practices related to water saving, water reuse, and the preservation of water quality, is crucial. Thus, the goal of the present study was to assess the Portuguese population’s awareness of sustainable water usage practices.
The main contribution of this paper is the comprehensive assessment of the Portuguese population awareness regarding various aspects of water sustainability through a large-scale questionnaire. This assessment identifies specific areas, particularly water reuse, where awareness is low despite a generally higher awareness of sustainable water usage practices. Additionally, the paper introduces metrics for determining overall awareness and improvement potential, which is crucial for grouping participants based on similar characteristics and for designing targeted interventions to enhance sustainable behaviors.
2. Related Work
Issues related to water and its sustainable usage have been examined in numerous studies worldwide, using varied samples including university students, middle school students, and the general population. In the 2015–2016 school year, Aydoğdu and Çakır [
10] undertook a study in Afyonkarahisar, Turkey, involving 1050 students from the 6th, 7th, and 8th grades. Their research focused on understanding attitudes and awareness regarding water usage among middle school students. Quantitative data collection involved administering a questionnaire where participants expressed their agreement with presented statements using a 5-point Likert scale (I absolutely agree, I agree, I am neutral, I don’t agree, I definitely don’t agree). According to the results obtained, the most frequent response was
I agree. Therefore, the authors concluded that middle-school students demonstrate a collective awareness of water usage, emphasizing that this result aligns with what would be expected in this demographic group. The analysis of the results, considering the socio-demographic characteristics of the sample, revealed that female students exhibited significantly higher levels of awareness regarding water usage compared to male students. Additionally, students with parents who were university graduates also demonstrated significantly higher levels. Conversely, a student’s grade level or their place of residence did not show a significant influence on their attitudes towards water usage. According to the authors, the results obtained from these interviews indicate that middle school students have a high level of water usage awareness. The interview findings also suggest that students possess sufficient knowledge about the importance of water awareness. Moreover, participants have demonstrated awareness regarding the importance of preserving water for future generations, an understanding of its significance for a livable world, and a recognition of both the individual and the societal responsibilities involved in furthering this awareness. Conversely, the interviews reveal a lack of knowledge among students regarding World Water Day, indicating a deficiency in the emphasis placed on such events within schools [
10].
Another study conducted among upper-school students in Pasir Mas, Kelantan, Malaysia, involving 242 6th form students, aimed to access the levels of knowledge, attitude, and practice of students concerning water resources sustainability [
11]. The research outcomes revealed that students exhibited elevated levels of knowledge and practices concerning the sustainability of water resources. In contrast, their attitudes in relation to water resource sustainability were deemed moderate. Furthermore, there were no significant variations found in the knowledge, attitudes, and practices regarding water resource sustainability among male and female students involved in the study. Regarding the correlation between the knowledge and practice variables, the authors identified a moderate correlation. Conversely, in the relationship between attitude and practice, the correlation was described as strong. Finally, the authors state that their study revealed a promising level of awareness among 6th form students regarding water resource sustainability. Consequently, they propose integrating education on water resource sustainability into the students’ curriculum and introducing extracurricular activities to guarantee that students recognize the importance of water resource sustainability in their daily lives.
A study conducted during the second semester of the 2023 academic year, involving 305 undergraduate students from Kasetsart University, revealed a generally high level of consciousness concerning sustainable water usage within the participants [
12]. Specifically, increased consciousness was noted in the realms of water conservation, hygiene practices, and culinary activities, while tree-care awareness was rated at a moderate level. Furthermore, the analysis based on demographic factors exhibited varying levels of sustainable water usage consciousness. The commonly utilized media platforms showed no discernible interdependence with the degree of sustainable water usage consciousness. Finally, the fact that the participants knows and understands issues related to sustainable water usage showed a weak interdependence with sustainable water usage consciousness.
Augustine and Hanafiah [
13] evaluated the level of understanding among students concerning the importance of water resources and their initiatives in conserving water across 10 residential colleges at Universiti Kebangsaan, Malaysia (UKM). In this study, a questionnaire survey was used, with the questionnaire consisting of three sections (i.e., demographic profiles, awareness level, and application). In the last two sections, participants expressed their opinions using a 5-level Likert scale (1—Strongly Disagree, 2—Disagree, 3—Unsure/Neutral, 4—Agree, and 5—Strongly Agree). The results from a sample size of 500 participants revealed a high level of awareness among UKM students regarding water resource conservation. Nevertheless, there was a significant gap in the implementation of water conservation practices among them.
Radzi et al. [
14] conducted a study focusing on water conservation awareness among students residing in Universiti Sains Malaysia hostels. The authors used a survey comprising multiple-choice questions administered to 214 students. Through analyzing the questionnaire responses, the researchers evaluated the students’ awareness of water conservation. The results indicated a limited level of awareness regarding water conservation among the students. The study suggests the need for the university to implement more impactful initiatives (e.g., the university water day) to raise students’ awareness about the water scarcity issues both nationally and globally.
During the 2011–2012 academic year, a study was conducted with 35 pre-service science teachers from the Environmental Science course at the Eskisehir Osmangazi University, Turkey [
15]. The study aimed to assess the impact of water education on participants’ awareness and found that a majority of participants stated concerns about future water-related challenges. These concerns encompassed issues such as the scarcity of usable water, insufficient education on relevant topics, unconscious water consumption patterns, and the pressures of population growth. Furthermore, the pre-service science teachers identified potential future problems including an uptick in contagious diseases, the struggle to access clean water sources, and looming water shortages. Within the participants, a considerable number expressed concerns that if unconscious water consumption persists without a promptly intervention, it could worsen water-related problems for future generations.
A study conducted among MSc students in University of Birmingham, United Kingdom, involving 299 individuals, aimed to investigate the subject of water consumption, particularly focusing on the water usage habits of students [
16]. To gain insights into students’ awareness and understanding of their domestic water consumption now and in the future, a questionnaire was administered over five academic years (from 2017 to 2021). The study’s findings reveal that master’s students tended to underestimate their water usage relative to the average observed across the UK. Furthermore, the results indicate a prevailing inclination among students to prioritize the adoption of water-saving technologies (40%) over behavioral modifications (27%). Considering these findings, the authors emphasize the importance of adopting a social practice theory perspective to effectively address water conservation challenges and promote significant changes in water usage patterns.
A study conducted with 1831 inhabitants of Albuquerque, New Mexico, a dry region in the USA, examined the impact of residents’ awareness of water scarcity and their belief in climate change on their willingness to use recycled water, both directly and indirectly [
17]. According to the study’s findings, inhabitants’ willingness to embrace direct recycled potable water is positively affected by their grasp of water scarcity, with the caveat that this influence is contingent upon their belief in climate change’s impact on the water cycle. Moreover, the propensity to accept indirect recycled potable water is shaped by the awareness of water scarcity, with a belief in climate change reinforcing this tendency. The authors point out these results underscore the importance of addressing climate change skepticism and raising awareness about water scarcity in the region to enhance the effectiveness and sustainability of long-term efforts in water conservation and climate change mitigation.
Another study conducted in Muscat, Sultanate of Oman [
18] aimed to explore public concerns and perceptions about the reuse of treated wastewater and to clarify how these perceptions could shape its current/future use. For this purpose, a survey questionnaire was carried out among 115 randomly selected residents. The study findings suggested that, overall, the public was familiar with water and wastewater terminology. Positive attitudes towards utilizing treated wastewater for various purposes such as irrigation, urban practices, groundwater replenishment, and industrial activities were noted. Conversely, options linked to human health, such as the discharge into aquatic environments and the reutilization for human consumption, were less favored. The authors stress that sharing knowledge and experiences is crucial for understanding and accepting wastewater reuse. They propose utilizing media channels to inform and enhance public awareness and engagement. Moreover, they also emphasize the need for more educational programs to raise awareness among younger people.
A study by Hussain et al. [
19] examined community awareness and public confidence in government-issued information on drinking water quality in Guangzhou (China) and Karachi (Pakistan). The study was based on questionnaire-based survey conducted over a six-month period in 2022. The findings indicate that in Guangzhou, awareness levels and positive attitudes among respondents were 46.2% and 30.0%, respectively. In Karachi, these levels were notably lower at 23.1% and 7.4%. Similarly, trust in media reports on water pollution accidents was higher in Guangzhou (76.0%) compared to Karachi (70.8%), while trust in government-provided information was also significantly higher in Guangzhou (79.3%) compared to Karachi (39.7%). The authors emphasize the need for increased awareness and more positive attitudes in both cities. Consequently, they recommend implementing enhanced public awareness campaigns in schools and community centers. They also suggest that non-governmental organizations could play a crucial role by organizing seminars and activities to enhance environmental knowledge and motivation among the general public. The study further calls for greater public participation in the development and execution of environmental policies to improve water quality standards.
Benameur et al. [
20] investigated public perceptions and awareness regarding drinking water quality, safety, and pollution events among residents of the province of Biskra, Algeria. Their study utilized a convenience sample of the general population, consisting of 300 residents of the province of Biskra, covering all age categories. The study revealed a concerning lack of awareness regarding water quality standards, as reflected in the priority given to taste (48.7%), odor (35%), appearance (34.7%), and color (32%) in water consumption profiles. Moreover, 55.7% of participants expressed dissatisfaction with the communication about preventive health measures regarding water quality. The authors highlight the influence of education level on perceptions of water quality and confidence in the safety of drinking water. The study’s findings emphasize the importance of policy makers and public health authorities considering these results to implement effective actions for preventing water contamination and protecting public health.
A study conducted in Kajang, Malaysia [
21] aimed to explore public awareness level regarding drinking water quality, pharmaceutical disposal, and the occurrence of pharmaceutical residues in drinking water and its potential health risks. To collect information, 89 randomly chosen residents were surveyed between May and September 2018. The findings indicate that the majority of participants demonstrated low knowledge (82.0%), a largely negative attitude (98.9%), and a moderate level of good practices (57.3%) concerning drinking water and pharmaceutical handling.
Tong et al. [
22] investigated the impact of awareness, perceptions, and individual behavior control on water conservation efforts, along with the role of gender, in these practices. A comprehensive survey involving 622 residents (318 women and 304 men) in rural northern China was carried out from April to August 2014 through personal interviews. The survey collected data on participants’ demographics and their attitudes towards water conservation, utilizing a Likert scale with five points. The study revealed that while respondents were highly aware of water conservation methods, their participation was low, especially among men. Women were more proactive in adopting conservation measures. The primary motivator for women was reducing water bills, whereas men were driven by the need to address water supply shortages. The noteworthy differences between genders underscore the importance of promoting transparency and communication across genders and between users and authorities in creating public policies and community initiatives. Such efforts are essential for mitigating gender disparities and foster wider acceptance of water conservation practices.
The importance of public awareness in attaining Sustainable Development Goal 6 cannot be understated [
23]. Thus, the authors undertook a study to explore its significance alongside other relevant factors in developing countries. The results unveiled several factors affecting households’ adoption of clean water, such as willingness to pay, social influence, governmental support, public awareness, and knowledge about water contamination. The authors suggest that the willingness to invest in clean water enhances the intention to utilize it. Thus, individuals who are inclined to invest in clean water are more likely to use it. However, upon becoming aware of the associated costs, especially due to their limited financial means, they hesitate to pay, expecting, instead, that the government provides clean water free of charge. Additionally, the authors highlight that in developing nations, financial constraints may take precedence over awareness and healthcare issues. The intention to use clean water is positively influenced by both social influence and governmental facilities, both of which are further enhanced by public awareness. Similarly, the results showed that awareness of the risks associated with contaminated water positively influences individuals to use clean water. Finally, the authors noted that demographic factors such as gender, age, and education did not influence a household’s intention to use clean water.
Given the research question and the fact that most questionnaires found in the literature focus primarily on the attitudes and behaviors of specific population groups regarding their water consumption habits, a questionnaire was designed, validated, and disseminated across Portugal to individuals representing a broad spectrum of demographics, encompassing both genders, diverse age groups, varied educational levels, and different regions of the country.