Clean water access improves child health in Mozambique, study shows

In Mozambique, more than one in three children under five suffer from stunting, or impaired physical growth, a sign of chronic undernutrition. New research from the University of Notre Dame shows that improving access to safe drinking water can reduce the odds of stunting by about 20 percent, making it the most effective Water, Sanitation and Hygiene (WASH) intervention for child growth.

The study, published in the journal Children, is one of the few studies to use nationally representative data from Mozambique to examine the independent and combined effects of access to water and sanitation on child growth outcomes (stunting and wasting). It also provides evidence-based policy recommendations for prioritizing clean water access, improving sanitation and tracking child growth to help guide interventions.

“Access to clean and safe drinking water is critical for preventing chronic undernutrition in children,” said Santosh Kumar Gautam, associate professor of development and global health economics at the University of Notre Dame’s Keough School of Global Affairs. “In Mozambique, where millions lack safe water, focusing on water interventions can have the greatest impact on stunting.”

Malnutrition remains a critical global health challenge, with the highest rates in South Asia and sub-Saharan Africa. While the World Health Organization highlights WASH as essential to preventing malnutrition by reducing diarrheal disease, environmental enteric dysfunction (an intestinal condition that causes inflammation and damaged gut lining) and impaired nutrient absorption, large gaps still remain. Nearly 2 billion people lack access to safe drinking water, and 3.6 billion lack access to safe sanitation.

Mozambique reflects this dual crisis. Recent data shows 56 percent of the population has access to basic drinking water and 31 percent to basic sanitation. In 2022, 37 percent of children under five suffered from stunting and four percent from wasting, or low weight for height. After steady improvements from 2000 to 2020, progress has since stalled. The economic impact of stunting is also high, with more than 11 percent of the gross domestic product lost due to undernutrition in Mozambique.

“There may be no perfect solution to stunting and wasting, but we can get as close as possible by following the evidence,” said Jailene Castillo, co-author of the study and a masters of global affairs student at the Keough School. “In Mozambique, despite widespread WASH programs, rates of stunting and wasting remain high. We wanted to understand whether WASH alone is enough to reduce malnutrition, a question no one had rigorously tested before.”

Notre Dame researchers analyzed health data from more than 3,500 children, drawn from the Mozambique Demographic and Health Surveys. The survey was conducted by Mozambique’s National Institute of Statistics in collaboration with the Ministry of Health in 2022–23, with technical support from ICF International. Using rigorous econometric methods, the study assessed associations between improved drinking water sources, sanitation facility types and child stunting and wasting. Two key WASH indicators — source of drinking water and type of toilet facilities — were analyzed separately and together.

The study found that after accounting for household and child factors such as wealth, region and religion, improved water access was initially associated with a 20 percent reduction in the odds of stunting. Improved sanitation showed no independent effect on stunting, and neither water nor sanitation had a consistent association with wasting.

“For a parent or caregiver, this means something simple: The safety of the water a child drinks every day can shape that child’s development for years,” said William Pater, a study co-author and biological sciences student at the University of Notre Dame. “For communities and decision-makers, it means that investing in clean, consistent water access may have a bigger impact on long-term child growth than sanitation alone. And because wasting did not respond clearly to either water or sanitation, it reinforces the need for timely nutrition support, infection treatment and social protection programs.”

Policy recommendations

Based on their findings, the researchers recommend that policymakers:

• Prioritize clean water access by expanding safely managed and basic water services and strengthening water-quality monitoring in regions with high stunting.
• Continue sanitation improvements for broader health and dignity benefits, while recognizing these changes may not produce rapid gains in child growth.
• Track progress using clear indicators on WASH access, water quality, disease burden and child growth metrics.

By identifying whether water or sanitation investments have stronger impacts on stunting or wasting, the researchers noted that policymakers in Mozambique and in similar low- and middle-income settings can better allocate resources to reduce child malnutrition.

Study co-author Gautam is affiliated with the Keough School’s Pulte Institute for Global Development as well as Notre Dame’s Eck Institute for Global Health and Building Inclusive Growth (BIG) Lab. Christina Molinaro, a graduate of Notre Dame, was also a co-author on the study.

Contact: Tracy DeStazio, associate director of media relations, 574-631-9958 or tdestazi@nd.edu