Published peer reviewed literature was screened and reviewed and peer reviewed journal articles that documented an educational or health effect associated with provision or absence of water and/or sanitation in schools selected. These impacts include an increase or decrease in school attendance, school dropouts, or any type of physical, social or psychological illness. The review was restricted to studies that explicitly explored the effects of the provision or absence of water, sanitation, and related hygiene materials such as soap, towels, and toilet paper in the school environment; studies that only examined the effects of behavior changes were excluded. Dissertations were not included. Articles without abstracts or full texts available were not included. Studies concerning day care centers were excluded. Studies on hand sanitizers were excluded.

We categorized ‘water’ interventions as either those for hand washing—including water, wash basins, soap, and drying devices, or for drinking. Studies considering only the impact of fluoride in drinking water were also excluded from the review, as the effects of fluoride on oral health in schools have been widely studied. Sanitation was defined as the availability of facilities to urinate or defecate (private, safe toilets, latrines, and availability of toilet paper) or as facilities for women and girls to manage menstruation (private location, and means for management or disposal of menstrual hygiene materials). Studies on the impact of availability of sanitary napkins were not included. The outcomes targeted by this review included health and educational outcomes. Health effects included in the study encompassed all of the defined social health, mental and physical health topics recognized by the National Institute of Health. Educational outcomes included school attendance and academic performance.

Studies were classified into seven non-exclusive categories: intervention trials, randomized control trials, observational studies, participatory research studies, descriptive studies, cross-sectional studies and outbreak investigations. Studies were also organized by economic status and field topic in order to better organize the results of the search.

The following major scientific, electronic databases were searched during the months of October through December 2010: PubMed, Embase, Web of Science, the Cochrane Library, Science Direct, and Google. In March 2012 a follow-up scan for subsequently published papers was conducted and five articles that met the inclusion criteria were added to the review.

The primary search was based on the keywords: Schools and Water or Sanitation, Gender and Water or Sanitation, Girls and Water or Sanitation, Menstruation and Water or Sanitation, School Absenteeism and Water or Sanitation, School Health Policies and Water or Sanitation, WASH (Water, Sanitation, and Hygiene) and Schools. All references in the bibliographies of included documents were also systematically searched for relevant documents. The study was restricted to documents for which an abstract and article in English was available.

The search included no time or location restrictions. Studies not written in English, or without an English translation available, were not included in this review. A secondary reviewer completed the review independently. Consensus was reached between primary and secondary reviewers in all cases of initial disagreement.

The primary search identified 3,485 publications whose titles discussed water provision, water quality or sanitation facilities in schools. The majority of these references came from scientific databases (n = 3,312), with the majority from PubMed (n = 2,025). The secondary screening based on abstract identified 471 relevant references. Thirty-nine articles met the inclusion criteria for the tertiary, full-text, review. Bibliographies of these articles revealed an additional six articles. Four of the 39 included studies were excluded from the library due to duplication in multiple papers; in these cases the most comprehensive article from each of these studies was included. Forty-one papers were included in the initial systematic review. Six more studies were added after the initial review, making forty-seven included studies used in data analysis (n = 47) (Figure 1).

Of the forty-seven papers, eleven addressed drinking water (23%), seven addressed water for handwashing (15%), five addressed providing water for drinking and handwashing (11%), six addressed sanitation (13%); four papers addressed sanitation related to menstruation facilities (8%); and fourteen addressed providing water and sanitation combined in schools (30%) (Table 1).

Many of the studies utilized more than one source of data. Twelve of the forty-seven studies included an experimental intervention (25%); twelve studies used interviews, questionnaires, or focus group and site observation (25%); fourteen studies were analyses of publicly-available data or questionnaires (30%); two studies performed solely site observations (4%); and nine studies included microbiological analyses of student stool samples, observations of sites and/or a questionnaire (19%).

The forty-seven included studies comprised nine intervention trials (19%); four randomized control trials (9%); one observational study (2%); one participatory research study (2%); four descriptive studies (9%); twenty-six cross-sectional studies (55%); and two outbreak investigations (4%) (Table 2). Characteristics of studies included in the review are highlighted in Table 3.

The health, cognitive and educational outcomes catalogued in the studies were: infectious diseases (including helminth infections, diarrhea, respiratory and other communicable diseases) (n = 20); gastrointestinal issues including constipation, incontinence, and urinary tract infections related to avoidance (n = 7); physical harm, (n = 2); dehydration (n = 6); obesity (n = 2); neuro-cognitive impacts including mental performance (n = 7); psychological outcomes such as shame or discomfort to use the toilet (n = 5); and absenteeism (n = 8). Seven studies documented outcomes of schools failing to serve as role models on hygiene (thereby undermining the efforts of teaching hygiene, which was not quantified) (n = 7). Educational outcomes included educational achievements and school attendance, while eight studies report absenteeism, only one study analyzed academic performance as an educational outcome [33] (Figure 2).

Studies were grouped into categories to more effectively describe the results. Articles were also analyzed to determine the differences in responses in developing vs. developed regions, as classified by the United Nations Statistical Division. However, the studies revealed similarities in reported inadequacies in facilities and in the stated benefits of provision of water and sanitation services [51]. This can be partially attributed to the locations studies were performed within the developed region. Many of the studies in developed countries were self-reported or designated as either from socially deprived, rural or overcrowded urban areas. All studies in South Wales (n = 12) were also considered to be conducted in deprived areas because of the water conditions reported in that part of the United Kingdom, including water shortages and inadequate sanitation facilities [11,12,26].

Eleven studies investigated drinking water provision and five examined both water for drinking and for handwashing combined [3,4,7,8,9,10,11,12,13,14,15,16,17,18,19,20]. All studies that exclusively investigated water for drinking were conducted in developed countries: ten studies in the United Kingdom and in the United States and one in Germany. Seven of the eleven studies measured the change in water consumption from increased water provision in schools [3,10,11,13,14,16], while four focused on the water quality issues relating to lead in school water [7,8,9,15]. All eleven studies reported inadequacies in provision of water for drinking and benefits of improving drinking-water provision in schools.

Two survey studies in schools in the United Kingdom documented inadequate water facilities such as water fountains potentially leading to inadequate hydration [3,10]. These studies cite the established effects of dehydration on health outcomes, such as decreased physical activity, mental capacity, and urinary tract infections. Three intervention studies documented a statistically-significant increase in water consumption when school children were allowed free access to water in school [11,12,13]. One further study, a randomized control trial, reported a 31% reduction in the risk of overweight associated with providing drinking water and education in schools in Germany [13].

In relation to water quality, four studies concerned lead in drinking-water fountains in schools in the United States [7,8,9,15]. These studies indicate the potential for significant lead exposure to occur due to lead contamination of school drinking water sources. The neurotoxic effects of lead on children, even at low doses, are well understood [52,53]. Though lead was found in school drinking water sources, blood lead levels were not tested in students in three out of the four studies [7,8,9]. Sathyanarayana et al., in 2006 tested the blood lead levels in students in a Washington State school after reports of lead levels above USEPA guidelines [15]. The study found that lead in school drinking water was not a significant source of lead exposure for students; the worst-case scenario geometric mean blood lead levels for 5–6 year old children in these schools ranged from 1.7–5.0 µg/dL; which is considered low for the state [15].

Seven studies examined handwashing in schools while five studies examined both water for drinking and for handwashing combined [25,26,28,29,30,31]. All studies used surveys or questionnaires, and validated findings through triangulation of data methods such as site observations, and analysis of school records. Three of the five studies that exclusively examine handwashing were conducted in developed countries [31,33,34], and all of the studies examining water for drinking and handwashing combined were conducted in developing countries [4,17,18,19,20]. This body of literature provided evidence for provision of water for handwashing and handwashing materials such as soap related to decreased absenteeism and reported illnesses as well as to increased handwashing knowledge.

Schools with scarce supplies for handwashing—such as water provision, soap, or towels—reported less handwashing [28,30]. Scarcity of supplies was noted in a United States survey study in 2007 on a college campus, revealing that 59% of residence halls on campus provided no soap and 90% no paper towels Thirty one percent of respondents indicated they did not wash their hands due to lack of supplies for handwashing [34]. The findings of the survey by Lopez-Quintero et al., in Colombia, indicate that children with access to handwashing materials were three times as likely to consistently wash their hands before eating and after toilet usage. In addition, those who reported proper handwashing (before meals, after toilet use) were statistically significantly less likely to report illness such as gastrointestinal and respiratory symptoms, and 20% less likely to be absent [28]. These surveys provide some evidence for a potential link between provision of handwashing services and handwashing behavior in school environments.

Three randomized control trials targeted at increasing provision of water for handwashing in Israel, China and Egypt reported dissimilar findings [25,29,31]. In their study in Israel, Rosen et al., performed a quasi-blinded handwashing study and found no significant change in rates of communicable illness or absenteeism despite sustained handwashing behavior after six months [29]. Bowen et al., conducted an experimental handwashing study in China in which the intervention groups experienced statistically significant lower rates of illness and of absenteeism [25]. Talaat et al., conducted a handwashing and education intervention in Cairo, Egypt and reported statistically significant declines in absences caused by illnesses such as diarrhea, conjunctivitis and laboratory confirmed cases of influenza [31].

Three of the six studies that investigated the combined effects of drinking water provision as well as water for handwashing reported decreased absenteeism and illness rates due to inadequate sanitation materials and facilities [17,18,19,20]. Blanton et al., performed interventions at seventeen Kenyan schools which provided handwashing and drinking water treatment sources and education of teachers [17]. They found a significant increase in household water treatment practices that was sustained over one year and reported a 26% decrease in pupil absenteeism after the implementation of the school-based programs [17]. Migele et al., found a statistically significant decrease in visits to the school nurse for diarrheal diseases in response to their interventions in Kenya which involved providing drinking water treatment and handwashing stations [19].

Six studies met the pre-defined search criteria for sanitation [32,33,34,35,36,37]. Five of the studies were conducted in a developed nation [32,33,34,36,37] and one in a developing [35]; all six document inadequacies in sanitation provision and the benefits of provision in schools.

Samwel and Gabizon highlight the need to build sustainable toilet facilities indoors in rural areas in Eastern European nations due to avoidance of outdoor toilets located far from the school buildings [36]. Outdoor toilets surveyed also displayed inadequate sanitation; many facilities had insufficient water availability and floors covered with urine which froze in winter [36]. Surveys by Barnes and Maddocks in the United Kingdom and Lundblad et al., in Sweden also documented avoidance of toilets observed as smelly, unclean and lacking privacy [32,34].

Overcrowding in schools was also associated with the avoidance of toilets. Students were reported to avoid using the toilet due to the anxiety of waiting in line during recess or lack of privacy [37].The avoidance of toilets may contribute to a higher risk of associated continence-related issues like urinary tract infections.

There was only one study that examined academic performance as an educational outcome, a study assessing the condition of school sanitation facilities in New York City by Duran-Narucki [33]. The study found that the condition of schools, as assessed using multiple indicators including school sanitation facilities, was related to students’ academic success and school attendance. In rundown school buildings students attended fewer days and exhibited poorer performance on math and English standardized tests [33].

Four studies focusing on the provision of water and sanitation facilities for menstruation management in the school environment met the search criteria [21,22,23,24]. Two were conducted in developing countries—South Africa [21] and Tanzania [24]—and two in a developed, the United Kingdom [22,23].

All four studies documented female discomfort in the school environment during menses due to inadequacies in the assurance of privacy, disposal of materials for menstruation, or sufficient school water and sanitation facilities. Economically developed countries may have sanitation facilities that enable females to privately manage menses due to an abundant supply of clean water, privacy, affordable sanitary materials and undergarments and may also have supportive female teachers and school nurses for managing menses [24]. However, deficiencies in sanitation facilities to manage menstruation in schools in the United Kingdom were reported in two cross-sectional studies [22,23]. Post-pubescent female schoolgirls in Tanzania and South Africa reported challenges to travel to and to attend school during menses due to the inability to afford sanitary materials as well as inadequate school facilities such as no running water or broken doors [21,24]. School girls in South Africa also reported a fear of using sanitation facilities due to sexual attacks in school toilets located far from the school building as well as avoiding schools during menstruation [21].

Fourteen studies focus on the combined effects of water and sanitation in schools [6,38,39,40,41,42,43,44,45,46,47,48,49,50]. Six of these studies were conducted in developed countries [41,43,45,46,47,50]; all of the studies document inadequacies in water and sanitation provision and the impact of provision in schools sampled. One observational study, eleven cross-sectional and two experimental studies were present in this body of literature.

Three studies reported inadequate water and sanitation facilities in schools through surveys and commentaries [41,43,45]. Six studies reported evidence on the lack of adequate sanitation facilities associated with greater risk of gastrointestinal and communicable infections [6,41,43,45,46,50]. Koopman’s 1978 epidemiologic study in Colombia reported statistically significant evidence for a causal relationship between the adequacy of toilets (toilet facilities that are not easily broken by students, adequate supply of water, cleanliness, and provision of toilet paper, soap and towels for drying) and diarrhea and vomiting in the schools observed [6]. In an outbreak investigation, Rajaratnam et al., documented that students who used toilets for defecation in a primary school in the United Kingdom were statistically significantly more likely to develop Hepatitis A due to inadequate sanitation facilities [46]. On investigation, the school involved in the outbreak was found to lack toilet paper, hand towels, and soap for handwashing [46]. Hughes et al., studied sanitation in the Pacific Islands and reported a decrease in the risk for helminthic infections when children have increased access to water for handwashing and relieving wastes [42]; reporting, that, regardless of water quality, children who attend schools without water supply are four times more likely to contract helminthiases than children who attend schools with water supply [42].