Water and sanitation

Sustainable Development Goal 6

Ensure availability and sustainable management of water and sanitation for all


Biodiversity supports several water-related ecosystem services which are essential to ensure the sustainability of water and to achieving Goal 6. Ecosystems underpin water quality and availability. Examples include wetlands that help to regulate floods, forests that contribute to providing clean water, and healthy biodiverse soils that support water availability for food crops.

Water is our most precious natural resource and central to sustainable development. A renewable but finite resource, it can be recycled but not replaced. Our planet’s water is facing severe pressure from increasing demands to satisfy the needs of a growing population, rapid urbanization, pollution and climate change. Estimates suggest that about 80% of wastewater from human settlements and industrial sources worldwide is discharged untreated directly into water bodies, with detrimental effects on human health and ecosystems. Water resources, and the range of services they provide, underpin poverty reduction, economic growth and environmental sustainability. Water supports all terrestrial life on Earth – including the entire human population. From food and energy security to human and environmental health, water contributes to improvements in social well-being and inclusive growth, affecting the livelihoods of billions. Water is required to support biodiversity. But Biodiversity is also required to support water.


Without sufficient water, stresses on species and ecosystems increase global biodiversity losses. In turn, biodiversity is critical to the maintenance of both the quality and quantity of water supplies and plays a vital but often under-acknowledged role in the water cycle and therefore in achieving Goal 6. According to the Food and Agriculture Organization of the United Nations (FAO), over 700 million people still lack access to an improved water source and 2.5 billion lack access to basic sanitation. Water scarcity affects 2.8 billion people worldwide, on every continent. Water crises have been listed as a top global risk by the World Economic Forum for four years running. Of all of the world’s water, only 0.03% is available as liquid freshwater at or near the land surface. This water supports all terrestrial and freshwater biodiversity, underpins most aspects of human welfare and is essential for sustainable development.

Agriculture is the largest user of water, accounting for 70% of total withdrawal. By 2050, agriculture will need to produce 60% more food globally, and 100% more in developing countries.

Global water demand for manufacturing is expected to increase by 400% from 2000 to 2050, much larger than any other sectors. Main increases will be in emerging economies and developing countries.

Ecosystems – including, for example, forests, wetlands and grassland – lie at the heart of the global water cycle. Vegetated land cover regulates water movement across land and water infiltration into soils. Biodiversity supports water and nutrient cycling in soils and therefore plants, including all food crops. Together these processes control land erosion and regulate water quality. Plant transpiration, in turn, is a major contributor to local and regional rainfall. Wetlands in particular have the ability to store water and hence some can assist in helping us regulate floods.

These functions of ecosystems operate at local, regional and global scales and offer opportunities to consider them as “natural water infrastructure” to be used in ways to achieve the same objectives as hard engineered infrastructure such as dams, pipelines, water treatment plants, irrigation systems, drainage networks and flood management embankments.

Natural infrastructure solutions work and in most cases offer cost-effective and sustainable solutions. Examples include:

- Using forests to protect water supplies;
- Wetlands or forest serving as buffer strips to recycle pollutants and hence improve water quality;
- Rehabilitating soil biodiversity and functions to deliver improved water availability to crops and hence improve food security, whilst simultaneously reducing water use and off-farm impacts;
- Replacing, or reducing running costs of, water treatment facilities by rehabilitating landscapes;
- Reducing flood, drought and erosion risks by restoring natural water storage in catchments, in particular using wetlands but also through restoring land cover and soil health;
- Protecting coastal communities from storms through strengthening coastal ecosystems as buffers;
- Addressing desertification through restoring land cover and soils to keep water where it is needed (in the ground).


  • Ecosystems, including forests, wetlands and grassland, lie at the heart of the global water cycle. All freshwater ultimately depends on the continued healthy functioning of ecosystems.
  • Without ecosystems, and the complex biological relationships and processes they support, the quantity and quality of global water resources would be severely compromised. Hence, water should be developed and managed sustainably and in an integrated manner to satisfy human needs while respecting biodiversity and ecosystems requirements.
  • Protected areas are an important tool for protecting the ecosystems that deliver water to urban and non-urban communities. For example, a 2003 report found that around a third (33 out of 105) of the world’s largest cities obtain a significant proportion of their drinking water directly from protected areas.
  • The value of wetlands for human beings is estimated at several trillion US dollars.
  • Without water food production stops, cities cease to function, economic activity halts, green forests turn to desert
  • Currently 884 million people (12.5% of the global population) live without safe drinking water and 2.5 billion people (40%) lack adequate sanitation.
  • In the 50 years from 1950 to 2000, human population growth has reduced the amount of available freshwater per person by 60%.
  • Using alternative water sources for energy production, such as sea or wastewater, helps reduce pressures on freshwater resources.
  • The current growth rates of agricultural demands on the world’s freshwater resources are unsustainable. Inefficient use of water for crop production depletes aquifers, reduces river flows, degrades wildlife habitats, and has caused salinization of 20% of the global irrigated land area.
  • Of the US$2.5 trillion economic losses from disasters so far this century, 70% are water-related.