Safe Water for All: The Case for Prioritizing WASH Interventions

Executive Summary

Access to clean water and adequate sanitation is among the most fundamental determinants of human health, dignity, and economic development. Yet in 2023, 2.2 billion people still lack access to safely managed drinking water, and 3.5 billion lack safely managed sanitation — a failure with lethal consequences. Diarrheal disease, almost entirely preventable with clean water and sanitation, kills approximately 1.4 million people annually, making it one of the top causes of death in children under five globally.

The solutions are neither technically novel nor prohibitively expensive. WASH — Water, Sanitation, and Hygiene — interventions have among the strongest cost-effectiveness evidence in development, yet the sector remains dramatically underfunded relative to its impact. This report makes the case for treating WASH as a frontline global health priority.

The Scale of the Problem

The WHO/UNICEF Joint Monitoring Programme provides the most comprehensive data:

• Drinking water: 2.2 billion people lack access to safely managed drinking water. 703 million people still lack even basic water services.
• Sanitation: 3.5 billion people lack safely managed sanitation. 1.7 billion lack any basic sanitation, and 419 million still practice open defecation.
• Hygiene: 2.3 billion people lack basic handwashing facilities with soap and water at home.
• Disease burden: WASH-related diseases cause approximately 1.4 million deaths annually, 90% of them in children under five. Diarrheal disease, the primary WASH-attributable killer, causes 525,000 child deaths per year; 88% are attributable to inadequate WASH.

Geographic concentration: Sub-Saharan Africa and Oceania have the highest rates of unimproved water access. South Asia, while improving, contains the largest absolute numbers of people without safely managed sanitation.

Why the Problem Persists

Infrastructure Gaps

Low-income countries lack the capital and institutional capacity to build and maintain piped water systems, wastewater treatment facilities, and sewage networks. Many urban areas have expanded faster than infrastructure, leaving informal settlements unserved.

Groundwater Contamination

In many rural areas, water sources are contaminated with biological pathogens from fecal matter, but also with naturally occurring arsenic (Bangladesh, India, Southeast Asia) or fluoride (East Africa, India), requiring treatment technologies beyond simple boreholes.

Behavior and Norms

Even when facilities exist, behavior change is required. Open defecation continues in areas with latrines because of social norms, preference, and habituation. Handwashing rates — especially at critical moments (after defecation, before eating) — remain low even in areas with water access.

Funding Gap

The WHO estimates the global WASH financing gap at $114 billion per year to meet the Sustainable Development Goal 6 (clean water and sanitation for all by 2030). Current annual investment is approximately $60 billion — half the required level.

Cost-Effective Interventions

Water Purification and Point-of-Use Treatment

Chlorination of water at the point of use — using products like WaterGuard — reduces diarrhea incidence by 25–40% in field conditions. Evidence Action's Safe Water Now program delivers chlorine dispensers at water collection points, achieving verified treatment at approximately $1–$2 per person per year. GiveWell rates this among the most cost-effective global health interventions.

WASH in Institutions

Schools and health facilities serve as high-density transmission points. WHO/UNICEF estimates 14–28% of child diarrhea cases could be prevented by universal WASH in health care facilities. The same investment in schools improves attendance and reduces acute illness.

Community-Led Total Sanitation (CLTS)

CLTS programs that trigger community-wide behavior change around open defecation have achieved verified open-defecation-free (ODF) status in thousands of villages across South Asia and Africa at low per-household cost. However, sustained behavior change requires follow-up support.

Handwashing Promotion

Meta-analyses find that handwashing with soap reduces diarrhea incidence by 25–30% and acute respiratory infections by 21%. School-based handwashing programs show particularly high returns due to concentration of contacts and behavior formation at early ages.

Economic Returns

The WHO estimates that every $1 invested in water and sanitation returns $4–$12 in economic benefits through reduced healthcare costs, increased labor productivity, and reduced time spent collecting water (predominantly by women). In regions with severe water scarcity, the returns are at the upper bound of this range.

Recommendations

1. Donate to Evidence Action (chlorine dispenser programs) and Water.org (financial access to water infrastructure) — both deliver WASH benefits at well-documented cost-effectiveness.
2. Advocate for SDG 6 financing — Close the $54 billion annual funding gap through ODA commitments and multilateral development bank financing.
3. Support WASH integration in health and education systems — the co-benefits for health outcomes justify prioritization even from a narrow disease-control lens.
4. Fund behavior change research — Understanding what drives sustained sanitation behavior change is a high-value research priority.

Further Reading

• WHO/UNICEF Joint Monitoring Programme (washdata.org)
• Evidence Action (evidenceaction.org)
• Water.org Impact Data (water.org/our-impact)
• GiveWell: Chlorine Dispensers for Safe Water (givewell.org)
• WHO: Health and Economic Benefits of Improved Water Supply and Sanitation (who.int)