Sanitation – unsafe water sources, poor access to basic handwashing facilities and unsafe sanitation are often linked. How does access to sanitation vary across the world? What are the health impacts of unsafe sanitation?
Diarrheal diseases – unsafe drinking water is a leading risk for diarrheal diseases. How many die from diarrheal diseases each year, and how can we prevent them?
Causes of death – unsafe water is a leading risk factor for death, especially at low incomes. What do people across the world die from?
Hunger and undernourishment – unsafe water can exacerbation malnutrition, especially in children. How does undernourishment differ across the world?
Unsafe water is one of the world’s largest health and environmental problems – particularly for the poorest in the world.
The Global Burden of Disease is a major global study on the causes and risk factors for death and disease published in the medical journal The Lancet.1 These estimates of the annual number of deaths attributed to a wide range of risk factors are shown here. This chart is shown for the global total, but can be explored for any country or region using the “change country” toggle.
Lack of access to safe water sources is a leading risk factor for infectious diseases, including cholera, diarrhoea, dysentery, hepatitis A, typhoid and polio.2 It also exacerbates malnutrition, and in particular, childhood stunting. In the chart we see that it ranks as a very important risk factor for death globally.
According to the Global Burden of Disease study 1.2 people died prematurely in 2017 as a result of unsafe water. To put this into context: this was three times the number of homicides in 2017; and equal to the number that died in road accidents globally.
An estimated 1.2 million people died as a result of unsafe water sources in 2017. This was 2.2% of global deaths.
In low-income countries, it accounts for 6% of deaths.
In the map here we see the share of annual deaths attributed to unsafe water across the world. In 2017 this ranged from a high of 14% in Chad – around 1-in-7 deaths – to less than 0.01% across most of Europe.
When we compare the share of deaths attributed to unsafe water either over time or between countries, we are not only comparing the extent of water access, but its severity in the context of other risk factors for death. Clean water’s share does not only depend on how many die prematurely from it, but what else people are dying from and how this is changing.
Death rates from unsafe water sources give us an accurate comparison of differences in its mortality impacts between countries and over time. In contrast to the share of deaths that we studied before, death rates are not influenced by how other causes or risk factors for death are changing.
In this map we see death rates from unsafe water sources across the world. Death rates measure the number of deaths per 100,000 people in a given country or region.
What becomes clear is the large differences in death rates between countries: rates are high in lower-income countries, particularly across Sub-Saharan Africa and Asia. Rates here are often greater than 50 deaths per 100,000 – in the Central African Republic and Chad this was over 100 per 100,000.
Compare this with death rates across high-income countries: across Europe rates are below 0.1 deaths per 100,000. That’s a greater than 1000-fold difference.
The issue of unsafe sanitation is therefore one which is largely limited to low and lower-middle income countries.
We see this relationship clearly when we plot death rates versus income, as shown here. There is a strong negative relationship: death rates decline as countries get richer.
Access to improved water sources is increasing across the world, rising from 76% of the global population in 1990 to 91% in 2015. This means 9% – nearly one-in-ten – do not have access to an improved water source.
In the map we see levels of water access across the world, measured as the percentage of the total population with access to improved water sources.
The definition of an improved drinking water source includes “piped water on premises (piped household water connection located inside the user’s dwelling, plot or yard), and other improved drinking water sources (public taps or standpipes, tube wells or boreholes, protected dug wells, protected springs, and rainwater collection).” Note that access to drinking water from an improved source does not ensure that the water is safe or adequate, as these characteristics are not tested at the time of survey. But improved drinking water technologies are more likely than those characterized as unimproved to provide safe drinking water and to prevent contact with human excreta.
In 2015, most nations had improved water access in greater than 90% of households. This marks significant progress since 1990 where most countries across Latin America, East and South Asia, and Sub-Saharan Africa were often well below 90%. Access remains lowest in Sub-Saharan Africa where rates typically range from 40 to 80% of households.
The share of the world without access to improved water sources has declined in recent decades. But how has the number without access changed?
The chart here shows the total number of people with and without access to an improved water source, globally. Note that these trends can be seen by countries and regions using the “change country” option.
In 1990, 1.26 billion people across the world did not have access to an improved drinking water source. By 2015, this had nearly halved to 666 million.
This improvement occurred despite strong population growth over this period. In 1990, 4 billion people had access to an improved water source; by 2015 this had increased to 6.7 billion. This means that over these 25 years the average increase of the number of people with access to improved drinking water was 107 million every year. These are on average 290,000 people who gained access to drinking water every single day.3
The chart shows the number of people without access to an improved water source by region. The regional breakdown of those without access has changed significantly over the past 25 years.
In 1990 nearly 42% of those without access were in East Asia & the Pacific. By 2015, this had fallen to 20%.
In contrast, Sub-Saharan Africa was host to 22% of those without water access in 1990; by 2015 this had increased to nearly half of the global total. In fact, the absolute number of people without access has fallen across all regions over this 25-year period with the exception of Sub-Saharan Africa. The number of people in Sub-Saharan Africa without access to an improved water source has increased from 271 million to 326 million in 2015.
In the map here you can explore the number of people without access to improved water sources across the world. Clicking on any country will show how this number has changed over time.
Having access to an improved water source increases the likelihood that drinking water is clean and safe. But it doesn’t guarantee that it is free from contamination.
Looking at ‘safely’ drinking water does guarantee this, although data is not currently available for all countries.
It’s estimated that only 71% of the world population has access to safe drinking water. This means 29% of the world does not have access.
In the map shown we see the share of people across the world that have access to safely managed drinking water.
29% of the world did not have access to safely managed drinking water in 2015. This equates to 2.1 billion people globally.
In the visualizations here we see the number of people globally with and without safe drinking water, and a world map of the number without access.
Both charts can be explored over time, and by country using the “change country” toggle, or by clicking on a given country on the world map.
Related chart – a global map of the number of people who use safe drinking water is available here.
In the visualization we see the number of people globally with different levels of drinking water coverage – ranging from ‘at least basic’ to surface water.
Globally, 6.5 billion people had access to ‘at least basic’ levels of sanitation in 2015. This left around 800,000 without even basic facilities.
This chart can be explored for a range of countries using the ‘change country’ toggle.
The visualisation shows the relationship between access to improved water sources versus gross domestic product (GDP) per capita. We see that there is a general link between income and freshwater access.
Typically most countries with greater than 90% of households with improved water have an average GDP per capita of more than $10,000-15,000. Those at lower incomes tend to have a larger share of the population without access. However, there are some notable exceptions: for example, more than half of Equatorial Guinea’s population lacks access to improved water despite having an GDP per capita above $27,000. In this case, the country’s wealth is highly concentrated; the mean GDP per capita is therefore far from the median GDP (i.e. there are high levels of inequality). Equatorial Guinea is one of the few remaining autocracies in the African continent. Its politics and governance therefore has a much stronger influence than average income.
Although income is an important determinant, the range of levels of access which occur across countries of similar prosperity further support the suggestion that there are other important governance and infrastructural factors which contribute. For example, Malawi has achieved a 90% access rate despite having a GDP per capita just over $1,000. Mozambique which has a similar income levels has just over 50% access.
In addition to the large inequalities in water access between countries, there are can also be large differences within country. In the charts we have plotted the share of the urban versus rural population with access to improved water sources and safely managed drinking water, respectively. Here we have also shown a line of parity; is a country lies along this line then access in rural and urban areas is equal.
Since nearly all points lie above this line, with very few exceptions — notably Palestine — access to improved water sources is greater in urban areas relative to rural populations. This may be partly attributed to an income effect; urbanization is a trend strongly related to economic growth.4
The infrastructural challenges of developing municipal water networks in rural areas is also likely to play an important role in lower access levels relative to urbanised populations.
Improved water source: “An improved drinking water source includes piped water on premises (piped household water connection located inside the user’s dwelling, plot or yard), and other improved drinking water sources (public taps or standpipes, tube wells or boreholes, protected dug wells, protected springs, and rainwater collection).”
Access to drinking water from an improved source does not ensure that the water is safe or adequate, as these characteristics are not tested at the time of survey. But improved drinking water technologies are more likely than those characterized as unimproved to provide safe drinking water and to prevent contact with human excreta. While information on access to an improved water source is widely used, it is extremely subjective, and such terms as safe, improved, adequate, and reasonable may have different meanings in different countries despite official WHO definitions. Even in high-income countries treated water may not always be safe to drink. Access to an improved water source is equated with connection to a supply system; it does not take into account variations in the quality and cost (broadly defined) of the service.” 5
Safely managed drinking water: “Safely managed drinking water” is defined as an “Improved source located on premises, available when needed, and free from microbiological and priority chemical contamination.”
‘Basic’ drinking water source: an “Improved source within 30 minutes round trip collection time.”
‘Limited’ drinking water source: “Improved source over 30 minutes round trip collection time.”
‘Unimproved’ drinking water source: “Unimproved source that does not protect against contamination.”
‘No service’: access to surface water only.
- Data: Access to improved water sources, improved sanitation facilities, open defecation, water consumption by sector and related health indicators
- Geographical coverage: Global – by country and world region
- Time span: 1990 onwards
- Available at: https://data.worldbank.org/indicator
- Data:Water and sanitation sources access
- Geographical coverage: Global – by country and world region
- Time span: 2000 onwards
- Available at: https://washdata.org/