Aim: The aim of this section is to provide you with information on what is meant by access to safe water and adequate sanitation, as well as to give you an overview of different health risks linked to lack of access to water and sanitation

3.3 Water

3.3.1 Introduction

Access to safe water and adequate sanitation are considered by the United Nations (UN) as a basic human right and are lack of access to these are linked to important environmental health issues, particularly in Low- and Middle-Income Countries (LMIC). Millions of people die every year from diseases associated with inadequate water supply, sanitation and hygiene. These 3 topics are often referred to as WASH (WAter, Sanitation and Hygiene).

The Sustainable Development Goals (SDG) were listed by the UN in 2015, as a sequel for Millenium Development Goals (MDG). The SDG 6 relates to “Clean water and sanitation”. As an introduction to WASH, watch this UN video on SDG 6.

Optional: Have a look at the SDG tracker website, for an overview of the progress on SDG 6.

3.3.2 WASH

The SDG 6 is about access to “safe water” and to “adequate sanitation”. To achieve this target, different points must be taken into consideration:

  • Do people have access to water sources and to sanitation facilities?

  • Do they use improved or unimproved source of water? improved or unimproved sanitation facilities?

  • What is the distance between household and water source?

  • Is the water quality good enough?

For this sub-section, please read this UN water webpage (including the “Facts and figures” column on the right hand-side), this UN document on “Human right to water and sanitation”, and watch this video. Access to water

Domestic water use only represents a small fraction of total water requirements (water is also needed for agriculture, industry, energy production…). It has been estimated that a minimum of 50L per person per day are required to supply basic requirements of an individual.

Access to water is a fundamental human need, but according to the UN over 2 billion people live in countries with high “water stress”. Please read this UN water webpage on water scarcity (including the “Facts and figures” column on the right hand-side). Moreover, access to water is inequitable: those suffering the most from lack of access to adequate water supply tend to be those who are already suffering from poverty. Access to sanitation

Please read this WHO factsheet on sanitation.

Inadequate sanitation increases the exposure to human faeces and thus leads to increased health risks (because they may contain pathogens). Access to sanitation is not equal, the majority of people without access to sanitation are poorer people living in rural areas.

In addition to health benefits, adequate sanitation has many other benefits: increased privacy; time-savings (not having to walk long distances to use public facilities), which may translate into increased production, education levels (the presence of available sanitation facilities in schools may play a role in encouraging children to attend school) or more leisure time… Improved access to water and sanitation

Please read this centre for Disease Control (CDC) webpage and these 2 WHO infographics on access to water and sanitation


Reprinted from WHO Progress on drinking-water, sanitation and hygiene, 2017: Infographics. Accessed June 10th, 2020

Also have a look at this UN illustration of the water and sanitation ladders

Access to safe water and to adequate sanitation is usually measured through access to an improved source of water and improved sanitation facility.

Great progress has been made over the past decade in terms of access to water: over 90% of the world’s population has now access to improved sources of drinking water. However, fewer progress has been made in terms of access to improved sanitation facilities. Time taken to access water source

The distance between household and the water source is also an important point to consider. The time needed to collect water has a significant effect on water consumption and thus on health. Basic access is sometimes defined as having a source within 1 kilometre or 30 minutes by walk of a water source. It is mostly women and children who are involved in water collection in LMIC. Freeing them from this task would allow women to spend more time in other tasks (work, education, caring for children, leisure, preparing food…) and children to spend more time at school.

This WHO table provides a good summary of requirement for water service level to promote health:

Source: (NB: l/c/d = litters per capita per day) Water quality

Another concern is the quality of the water. There are 2 main sources of water contamination:

  • Biological contamination: linked to the presence of pathogens in water. It is the primary concern for water quality. It may be in the form of bacteria, viruses, helminths (worms)…

  • Chemical contamination: chemical contaminants may be natural or a result of human activity

The WHO has published some Water quality guidelines, which provides water quality standards. The implementation of these guidelines varies across countries.

In high-income countries (HIC), water-related diseases are becoming rarer and with industrialisation, heath risk due to chemical water pollution has become the main concern. In LMIC, water-related diseases are the greatest source of concern, although the concern about industrial chemical pollution is increasing as well.

Optional: If you want to know more about this topic, you can read the WHO guidelines for water quality.

3.3.3 Water-related diseases

Insufficient quantity or quality of water is a threat to human health. This video is a good introduction to diseases related to water and sanitation.

Water-related diseases are divided in 4 types of diseases (Bradley classification of diseases): water-borne, water-washed, water-based and water-related vector-borne diseases. The key information is summarized in the subsections below. Water-borne diseases

Water-borne diseases relate to diseases spread through contaminated drinking water, mainly by ingestion of faecal material in water. Pathogens associated with human faeces can cause diarrhoeal diseases as well as other types of diseases. Some examples of water-borne diseases are: cholera, typhoid, hepatitis A and E…

Cholera is a severe diarrhoeal disease caused by the bacteria Vibrio cholerae. People can die within a few days because of untreated dehydration. As an example of water-borne diseases transmission and prevention, watch this video on cholera.

Optional: For more details read this WHO factsheets about Cholera, typhoid and hepatitis. Water-washed diseases

Water-washed diseases are diseases which can be prevented by increased quantities of water for washing and cleaning. The 2 main examples are trachoma and scabies.

  • Trachoma is the consequence of eye infection by Chlamydia trachomatis (bacteria). It is a painful eye disease and the world’s leading infectious cause of blindness.

  • Scabies is a contagious skin infection, preventable with improved personal hygiene. It is caused by Sarcoptes scabei.

Optional: If you want more information, you can read the WHO factsheets on trachoma and scabies. Water-based diseases

Water-based diseases are diseases for which the causing agent spend part of their life cycle inside an aquatic host. Infections are spread either through skin penetration while bathing in contaminated water or through ingestion. Water-based diseases include:

  • Schistosomiasis: larval forms of the parasite grow inside freshwater snails. They are then released into the water and can penetrate the skin of people who are bathing or in contact with the water. The symptoms include abdominal pain, diarrhoea, haematuria…

  • Guinea worm (Dracunculus): It can only be ingested by drinking water that contains a crustacean, called “water fleas”, which contain the worm. Worms are released in the human intestines, and migrate to the skin, forming a blister or swelling (most often in the legs). It is the target of an international eradication campaign.

Optional: If you want more information, you can read the WHO factsheets on schistosomiasis and Guinea worm. Water-related vector-borne diseases

Water-related vector-borne diseases are diseases spread by insects that either breed in water or are found near water. Examples of this type of diseases are malaria, dengue, yellow fever…

Malaria is transmitted by a mosquito (Anopheles) which carries a parasite called Plasmodium. The first symptoms include fever and headache; the following symptoms include severe anaemia, respiratory distress and can lead to death. It is the most significant water-related vector-borne diseases.

Optional: If you want more information, you can read the WHO factsheet on Malaria.

Optional: For further information about the Bradley classification of diseases, you can download this paper.

3.3.4 Conclusion Preventing WASH related diseases

Four types of interventions can be used to tackle WASH related diseases: water supply interventions, water quality interventions, hygiene interventions, sanitation interventions.

  • Sufficient water quantity enables hand washing and safer food preparation

  • Improved water quality prevents diseases transmission through contaminated drinking water

  • Good hygiene practices minimise transmission (e.g. hand washing)

  • Adequate sanitation facilities act as a barrier to prevent faecal contamination of water

Case Study

Yemen is a war-torn country that recently endured the worst cholera outbreak in history. As mentioned above, cholera is a bacterial disease caused by food and water contamination. The disease is a global health issue, especially in developing countries with limited access to clean water. This

by the UN Humanitarian shows how water treatment supported by UNICEF can dramatically reduce cholera in a short period of time.

This video by Médecins Sans Frontières Australia & New Zealand also shows ways to control the spread of the disease. Water scarcity, climate change and impacts on WASH

Water scarcity, resulting from unsustainable consumption of water (human overuse of water resources) and climate change, is a major threat to human health and future economic and social development.

Climate change may affect access to water and adequate sanitation by increased risks of floods and droughts, and may result in scarcity and contamination of drinking water. Increased water scarcity may result in increased competition for freshwater use (domestic, agricultural and industrial use).

Given the complexity of the problem, successful policies to achieve the SDG 6 will require cooperation from different sectors (agriculture, health, energy, environment…).

As a conclusion to this sub-section, please watch this video on water crisis.

Optional: You can watch this TED talk on SDG 6.


Last modified: Monday, June 7, 2021, 11:37 AM