Water security

Water surplus and deficit

is having enough clean water for people's needs, and for farming and industry. is when there isn't.

A is where supply is greater than demand, as in wet, thinly populated areas.
A is where demand is greater than supply.
is when there isn't enough water of good enough quality to meet people's needs.

According to the World Health Organization and UNICEF, 2.1 billion people lacked safely managed drinking water in 2024, 1 in 4 of the world's population. Water stress is highest in North Africa, the Middle East and parts of South Asia.

Key terms

Why consumption is rising

Population growth: more people need water for drinking, cooking and washing.
as countries develop, people use more water at home, with showers, washing machines and dishwashers.
Industry: factories and power stations need huge amounts of water.
Farming: uses more water than anything else. As more food is grown, especially meat, which needs water for crops to feed the animals, demand rises.

Key terms

What affects water availability

Climate: low or unreliable rainfall, and high temperatures, which increase evaporation. Climate change is making some regions drier.
rocks that store water underground, called , provide water; impermeable rocks don't.
Pollution: sewage, factory waste and farm chemicals make water unsafe.
taking more water from rivers and aquifers than is replaced, so wells run dry.
pipes, treatment works and reservoirs are costly, and many poor areas lack them.
Poverty: poor families can't pay for water, or for wells or pumps.

Key terms

The impacts of water insecurity

Disease: dirty water spreads , such as cholera and diarrhoea, which kill many young children.
Food production: without water for irrigation, crops fail and food prices rise.
Industrial output: factories and power stations can't work without water, so jobs and growth suffer.
Conflict: countries can disagree over rivers they share, when one takes water that others need downstream.
Time and education: in many places, women and girls spend hours fetching water, instead of working or going to school.

Exam tip

Explain each impact as a chain of effects, with an example.

Key terms

Exam practice

Plan your own answer first, then open the model answers to see what each level looks like.

6 marks · about 6 minutes

Explain the factors that affect the availability of water.

Explain means: Give the reasons why something happens, developing each point with "because" or "so".

Level 1 (Basic)· 2/6 marks (band 1–2)

Some places have little rain, so there is less water. Pollution can make water unsafe.

Why this level: Two relevant factors, stated simply. To reach Level 2: explain several factors and how each reduces the water available.

Level 2 (Clear)· 4/6 marks (band 3–4)

Low or unreliable rainfall reduces water, and high temperatures increase evaporation. Pollution from sewage and factories makes water unsafe to use. Over-abstraction takes water from wells faster than it is replaced, so they run dry.

Why this level: Clear explanation of several factors. To reach Level 3: develop more factors, such as geology and infrastructure, and add more detail.

Level 3 (Detailed)· 6/6 marks (band 5–6)

Climate is a major factor: low or unreliable rainfall reduces supply, and high temperatures increase evaporation from rivers and reservoirs; climate change is making some regions drier. Geology matters: permeable rocks can form aquifers that store water underground, but impermeable rocks can't. Pollution from sewage, factories and farms makes water unsafe to drink. Over-abstraction takes water from rivers and wells faster than it is replaced, so wells run dry and rivers shrink. Finally, pipes, treatment works and reservoirs are expensive, so many poor areas lack them, and people may have water nearby but no safe supply.

Why this level: Detailed explanation of physical and human factors, each developed and linked to availability. This is Level 3.

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