The Importance of Water and Sanitation: Key to Sustainable Development

Clean water flowing from a tap and a safe toilet to use are things many of us rarely think twice about. Yet for millions of people, especially those living in crowded urban settlements, these basics remain out of reach. Water and sanitation sit at the very foundation of human health, dignity, and economic progress, which is why the United Nations recognises them as fundamental human rights and a core pillar of sustainable development.

Understanding water and sanitation
Why water and sanitation matter
The economic and social weight of WASH
Global efforts for water and sanitation
The International Drinking Water Supply and Sanitation Decade (1981-1990)
From the Millennium Development Goals to SDG 6
Water and sanitation challenges in urban slums
Inadequate water supply
Unsafe sanitation facilities
The disease burden
Why slums are stuck
The road ahead

Understanding water and sanitation

Water and sanitation are two interlinked services that together protect human health and enable everyday life. Safe drinking water refers to water that is accessible on premises, available when needed, and free from faecal and chemical contamination. Sanitation refers to facilities and systems that safely manage human excreta, wastewater, and solid waste so that they do not contaminate the environment or the people living in it.

When combined with hygiene practices such as handwashing with soap, these services form what global health experts call WASH: Water, Sanitation, and Hygiene. The United Nations describes access to safe water, sanitation and hygiene as the most basic human need for health and well-being, a reminder that without these services, nearly every other development goal becomes harder to achieve.

Why water and sanitation matter

The link between WASH and health is direct and well documented. Unsafe water and poor sanitation are leading causes of diarrhoeal diseases, cholera, typhoid, hepatitis A, and several neglected tropical infections like intestinal worms and trachoma. Children under five are particularly vulnerable, since repeated bouts of diarrhoea damage their ability to absorb nutrients and lead to stunting.

The benefits of getting WASH right go far beyond avoiding illness. According to a WHO analysis, every US$1 invested in sanitation generates roughly US$5.50 in returns through reduced health costs, higher productivity, and fewer premature deaths. Safe water also frees up time, particularly for women and girls who often bear the burden of fetching water from distant sources, and improves school attendance because children fall sick less often and girls are not forced to drop out due to a lack of private toilets.

The cost of inaction is enormous. A widely cited Water and Sanitation Programme estimate found that inadequate sanitation alone cost the country about ₹2.44 trillion (around US$53.8 billion) per year, equivalent to roughly 6.4 percent of GDP in 2006. That loss came from premature deaths, healthcare expenses, productivity drops, and time lost to fetching water or seeking care for preventable illnesses.

WASH is also a question of dignity and safety. Open defecation, the practice of relieving oneself in fields, drains, or open spaces, exposes women and girls to harassment and violence, especially after dark. Separate, functional toilets in schools are strongly linked to higher attendance among adolescent girls, particularly after they begin menstruating.

Global efforts for water and sanitation

The international community has been working on these problems for decades. The story of organised global action really begins with the 1977 United Nations Water Conference at Mar del Plata, which laid the groundwork for the first major coordinated push on this issue.

The International Drinking Water Supply and Sanitation Decade (1981-1990)

Declared by the United Nations following the Mar del Plata conference, this initiative aimed to provide safe drinking water and basic sanitation for everyone by 1990. It was an ambitious target rooted in the belief that water and sanitation are inseparable from primary health care and the broader “Health for All” agenda of the World Health Organization.

The decade brought real, measurable gains. By its close, the programme had brought water to over 1.2 billion people and sanitation to nearly 770 million. Urban water coverage in developing regions rose from 77 percent in 1980 to 82 percent in 1990, while rural coverage jumped from 30 percent to 63 percent over the same period.

However, the decade did not meet its universal goal. Rapid population growth, fragmented governance, weak technology transfer, and a focus on small privileged urban areas at the expense of vast rural populations all hampered progress. The lessons from this experience, especially the need for community participation, intersectoral coordination, and locally appropriate technology, shaped every WASH programme that followed.

From the Millennium Development Goals to SDG 6

After 1990, the conversation moved into the Millennium Development Goals, which set a target of halving the proportion of people without sustainable access to safe drinking water and basic sanitation by 2015. That baton has now passed to Sustainable Development Goal 6, which aims to ensure availability and sustainable management of water and sanitation for all by 2030. SDG 6 covers eight targets, including universal access to safe drinking water, ending open defecation, improving water quality by treating wastewater, and protecting water-related ecosystems.

Despite decades of work, the gap remains huge. The UN reports that in 2024, 2.2 billion people still lacked safely managed drinking water, 3.4 billion lacked safely managed sanitation, and 1.7 billion did not have basic hygiene services at home.

Water and sanitation challenges in urban slums

Nowhere is the WASH crisis more visible than in the dense, informal settlements that ring most fast-growing cities. Urban slums are characterised by overcrowding, insecure tenure, and the lack of one or more essential services: durable housing, sufficient living space, clean water, and improved sanitation.

Inadequate water supply

Slum residents often rely on shared public taps, hand pumps, or private water vendors who charge much more per litre than what middle-class households pay through a metered connection. Supply is usually intermittent, sometimes available for only an hour or two a day, which forces families to store water in containers that can become contaminated.

Studies from Indian cities have repeatedly shown this pattern. In a cross-sectional study of urban slums in Jammu, 82.5 percent of households had access to improved drinking water sources, but the share with piped connections inside the home was significantly lower than the national average. Even where the source itself is “improved”, contamination during transport and storage often defeats the purpose. Point-of-use contamination of municipal water has been documented as a major cause of diarrhoeal disease among children in Indian urban slums.

Unsafe sanitation facilities

Sanitation tends to lag even further behind water supply. Many slum households share community toilet blocks that are poorly maintained, lack water, or remain locked at night. In the worst cases, residents resort to open defecation along railway tracks, drains, or vacant land.

The Swachh Bharat Mission, launched in 2014, has significantly expanded access to toilets and reduced open defecation, with a National Sample Survey Office assessment finding that 98 percent of toilets were being used in urban areas by 2018. Yet a study of slums in Lucknow noted that pockets of poor sanitation, irregular waste collection, and inadequate environmental cleaning still persist, undermining the health gains the mission was meant to deliver.

The disease burden

The consequences of these gaps fall hardest on children. Repeated infections of diarrhoea, typhoid, and cholera in slum settings drive up child mortality and contribute to chronic malnutrition. Research on urban slums in Kolkata has linked poor WASH practices to a high burden of enteric fever and other water-related infections, with overcrowding, low income, and weak hygiene knowledge acting together to worsen outcomes. Globally, WHO data attribute hundreds of thousands of deaths every year to unsafe WASH, with the heaviest toll in low- and middle-income countries of South Asia and Sub-Saharan Africa.

Why slums are stuck

The reasons slum WASH conditions are so persistent are structural. Many settlements are not formally recognised, which means municipal authorities are reluctant to extend piped networks or sewer lines into them. Land tenure insecurity discourages residents from investing in private toilets. Local governments are often underfunded and stretched thin, and the sheer pace of urban migration means that demand grows faster than infrastructure can be laid. WHO emphasises that sustainable sanitation requires not just toilets but the entire chain of safe management, from containment to treatment and disposal of waste, a chain that is almost entirely missing in most informal settlements.

The road ahead

Closing the WASH gap will need more than infrastructure. It needs governance reform so that informal settlements are recognised and served, community participation so that residents have a stake in maintaining facilities, behaviour change communication so that handwashing and safe water storage become habits, and steady financing to keep services running long after the ribbon is cut. It also needs joined-up thinking with other sectors, since better WASH supports better nutrition, education, women’s safety, and climate resilience all at once.

The story of water and sanitation is ultimately a story about what societies choose to prioritise. Decades of effort, from the 1981 Water Decade to SDG 6, have proven that progress is possible when political will, community action, and adequate funding come together. The unfinished part of that story now rests largely in the alleys of our cities.

What do you think? If you were designing a WASH programme for a slum settlement near you, would you start with toilets, water taps, or community awareness, and why? And how can young professionals in fields outside public health, like architects, engineers, or data scientists, contribute meaningfully to closing the WASH gap?

References

PDF 📄

The Importance of Water and Sanitation: Key to Sustainable Development

Table of Contents

Understanding water and sanitation 🔗

Why water and sanitation matter 🔗

The economic and social weight of WASH 🔗

Global efforts for water and sanitation 🔗

The International Drinking Water Supply and Sanitation Decade (1981-1990) 🔗

From the Millennium Development Goals to SDG 6 🔗

Water and sanitation challenges in urban slums 🔗

Inadequate water supply 🔗

Unsafe sanitation facilities 🔗

The disease burden 🔗

Why slums are stuck 🔗

The road ahead 🔗