Around 80% of the global population experience water insecurity. Water supply and consumption are not evenly distributed.
The UK has an overall water surplus although there are variations in the amount of rainfall across the country, for example places in the west receive much more rainfall than those in the east. There are also variations in the population density, eg the south east has a much higher population density than Wales, which is in the west.
In the UK, there are systems in place to transport water from areas of surplus to areas of deficit. These are called water transfer schemes and they can be found in many parts of the UK. One example is Kielder reservoir in Northumberland. Kielder is located in an area of high land and so the rainfall there is higher than many surrounding areas. Rainwater that collects in Kielder reservoir is transported southwards and released into rivers that flow to the cities and towns of Newcastle-upon-Tyne, Sunderland, Durham, Darlington and Middlesbrough.
In the past, people used far less water. Water use has increased as more people wash cars, take longer showers and water their gardens. The average person uses around 150 litres of cleaned and treated water every day. Farming and industry also use large quantities of water.
Only a proportion of the UK's total water use comes from within the country. Imported products, like food and cotton, use up water resources in the countries where they are grown. The UK's water footprint is a measure of the total water used both within the UK and in other countries through imported products.
The UK government has also considered creating a national water grid. This would work in a similar way to the national electricity grid, but it would be used to link up the country's water supplies.