London is classed by the Environment Agency as 'seriously water stressed'. The region's large population means that even during an average year, all the capital's fresh water supplies are already in use.
London actually receives less rainfall per person than Rome, Istanbul, Dallas or Sydney.
The volume of water we can take from rivers and groundwater sources, to treat and turn into drinking water, is limited by licences from the Environment Agency. These controls are set in order to protect the environment.
Pressure on water resources will continue to grow in the future. Another 700,000 people are forecast to be living in London by 2021, and climate change will increase the likelihood of longer, hotter summers.
As London's water company, we have a responsibility to make sure there is always plenty of water to go round. We need to be able to meet our customers' needs, even during a long-term drought.