01
Water
Safe and reliable water is fundamental to health, nutrition, hygiene and everyday life.
GLOBAL HEALTH · SUBJECT
Water, Sanitation & Environment
What surrounds us can shape our health.
Water, sanitation, hygiene and the environment are deeply connected to human health. Explore how access, safety, infrastructure, inequality and environmental change shape health around the world.
Self
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Family & Peers
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Community
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Country
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World
WHY IT MATTERS
Health does not happen in isolation.
The water we drink, the sanitation systems around us, the hygiene practices we can access and the environment in which we live all influence health.
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Sanitation
Safe sanitation helps prevent exposure to human waste and protects people and communities.
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Hygiene
Hand hygiene and other everyday practices can reduce exposure to infectious hazards.
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Environment
Pollution, climate change, ecosystems and water resources can influence health across generations.
WATER
One in Four Still Lacks Access to Safe Drinking Water
In 2024, about three quarters of the world's population used safely managed drinking-water services. That means approximately one in four people were still outside this highest service level.
74%
of the global population used safely managed
drinking water in 2024
≈ 1 in 4
people did not use safely managed drinking water
GHE DATA INVESTIGATION
Where is safe drinking water still out of reach?
Explore the map. Look for patterns. Which countries stand out? What questions does the map make you ask?
Read the map
More than 50%
lack safely managed drinking water
25–50%
lack safely managed drinking water
1–24%
lack safely managed drinking water
Almost universal coverage
No data
Mexico
According to this map's classification, Mexico is among the countries where more than half of the population lacks safely managed drinking water.
What might help explain this situation?
Scandinavian countries
Several Scandinavian countries appear in categories showing almost universal coverage of safely managed drinking water.
What factors might contribute to this level of coverage?
THINK LIKE A DATA DETECTIVE
Why can access to such a basic necessity differ so dramatically between countries?
Do not stop at the map. Consider infrastructure, geography, income, governance, urbanization, climate, water resources, historical investment and inequality. Then ask which explanations require additional evidence.
DATA LITERACY
Safe water is more than having a source.
Global monitoring distinguishes different levels of drinking-water service. Understanding these categories prevents us from treating very different situations as if they were the same.
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Safely managed
Drinking water is from an improved source, available when needed and located on premises, with the required safety conditions.
02
Basic service
An improved drinking-water source is accessible with a collection time of 30 minutes or less for a round trip.
03
Limited service
An improved source is available, but collection takes more than 30 minutes for a round trip.
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Unimproved source
Drinking water comes from a source that does not meet the definition of an improved source.
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Surface water
Water is collected directly from rivers, lakes, ponds, streams, canals or irrigation channels.
Important distinction:
“Lacks safely managed drinking water” does
not mean “has no drinking water.”
Different populations may use different levels
of service.
SANITATION
Safe sanitation protects health.
Sanitation is not simply about having a toilet. Safe sanitation also involves preventing human waste from contaminating people, water, food and the wider environment.
In 2024, approximately 58% of the world's population used safely managed sanitation services.
58%
safely managed sanitation
From sanitation to health
Waste management
→
Less contamination
→
Lower exposure
→
Better health protection
Safe sanitation is therefore part of a broader public-health system.
HYGIENE
Hygiene connects infrastructure with everyday action.
Even when people understand good hygiene practices, they may not always have the water, soap or facilities needed to put those practices into action.
80%
Basic hygiene services
In 2024, approximately 80% of the global population had access to basic hygiene services.
That still left approximately 1.7 billion people without basic hygiene services.
WATER + SANITATION + HYGIENE
WASH is a health issue.
Water, sanitation and hygiene are connected to infectious disease prevention, child health, nutrition, school participation and the resilience of health systems.
Infectious diseases
Unsafe water, sanitation and hygiene can increase exposure to pathogens and contribute to the spread of infectious diseases.
Child health
WASH conditions can influence children's exposure to infection and their broader health and development.
Nutrition
Repeated infections and unsafe environmental conditions can interact with nutrition and children's health.
Schools
Safe water, sanitation and hygiene can help create healthier learning environments.
Health systems
Health-care facilities need reliable WASH services to provide safe and dignified care.
Human dignity
Access to safe water and sanitation is connected not only to health, but also to dignity, safety and participation in daily life.
HEALTH EQUITY
The global average can hide major differences.
A national average tells us something important—but it does not tell us whether everyone has the same experience.
Rural & urban
Access to safely managed drinking water can differ substantially between rural and urban populations.
Income
Household resources, infrastructure and public investment can influence access to services.
Fragile settings
Conflict, displacement, disasters and weak infrastructure can disrupt essential services.
Gender
Water collection, sanitation and hygiene can have different consequences for women and girls.
Disability
A service may technically exist but still be inaccessible if facilities are not designed for different needs.
Marginalized communities
Historical and structural inequalities can shape access to essential environmental services.
GHE EQUITY QUESTION
Equal access is not simply about the national average. Who may still be left behind?
ENVIRONMENT
Water health depends on environmental health.
Rivers, lakes, groundwater, wetlands and coastal ecosystems are part of interconnected systems. Pollution and unsustainable use can affect both ecosystems and human health.
Water quality
Wastewater
Pollution
Ecosystems
Water stress
Climate change
Think beyond the tap.
Where does water come from? Where does wastewater go? What happens when rainfall changes? What happens when rivers or groundwater are polluted? How might climate change alter these systems?
BEYOND THE HOME
What about schools and health-care facilities?
Students can bring global health back to places they know: their school, community and local health system.
447M
Children
In 2023, approximately 447 million children lacked basic drinking-water services at school.
427M
Children
Approximately 427 million children lacked basic sanitation services at school.
646M
Children
Approximately 646 million children lacked basic hygiene services at school.
YOUR WORLD
Look at your own school.
Where are drinking-water points? Are they accessible? Are sanitation facilities safe and usable? Is soap available? What could students learn from observing their own environment?
DATA DETECTIVE
Before you interpret the number, interrogate the data.
Good global-health investigators do not simply ask “What is the number?” They ask what the number means.
01
What is being measured?
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Who is the denominator?
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What does “safe” mean?
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What year is being measured?
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Which population is included?
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What is missing from the data?
DATA DETECTIVE CHALLENGE
A country can have high national coverage while some communities remain underserved. A global average can improve while inequalities persist. Always ask: “Who is included in this number—and who might be hidden behind the average?”
SDG
6
SUSTAINABLE DEVELOPMENT GOALS
Clean Water & Sanitation
SDG 6 aims to ensure availability and sustainable management of water and sanitation for all.
Drinking water
Universal and equitable access to safe and affordable drinking water.
Sanitation & hygiene
Adequate sanitation and hygiene for all, with attention to vulnerable groups.
Water quality
Improve water quality and reduce pollution and untreated wastewater.
Water efficiency
Improve water-use efficiency and address water scarcity.
Water management
Strengthen integrated water-resource management.
Ecosystems
Protect and restore water-related ecosystems.
GHE DATA CHALLENGE
Test your thinking
These questions are not only about remembering facts. Use the map, the categories and the evidence to reason like a young global-health investigator.
Question 1 of 12
What does the red category mean on this map?
According to the map, which statement best describes Mexico?
Which statement best describes the Scandinavian countries shown on the map?
A student says: “The map proves that every person in Mexico has unsafe drinking water.” What is wrong with this statement?
You compare Mexico with a Scandinavian country on this map. What is the most appropriate question to ask next?
What can this map tell us most directly?
Why is “safely managed” different from simply having access to an improved water source?
Why should students distinguish between “water quantity” and “water safety”?
What is an important purpose of safely managed sanitation?
Why can hygiene be considered both a health behaviour and an infrastructure issue?
A country reports high national water coverage. What should a health-equity investigator ask next?
Which statement best connects water and the environment?
Your score
0 / 12
Keep exploring.
Global health is about asking better questions, not simply knowing more facts.
EXPLORE → LEARN → THINK → CONNECT → REFLECT → ACT
Every difference matters. Explore it.
Start with a map. Ask a question. Find evidence. Compare experiences. Listen to communities. Then think about what responsible action could look like.
Explore
What difference do you see?
Think
What might explain it?
Connect
Who is affected?
Act
What could be improved?