The Lower Thames reservoirs that supply London were 53.1% full at the end of September 2026, down from 59.4% a month earlier, according to the Environment Agency. Thames Water's hosepipe ban, in force since 23 July 2026, was still in place at the company's 12 October update.
A dry year from the start
The shortfall began in spring, when the Thames Water region received 40% of its average rainfall. September brought 31 mm to the Thames area, 53% of the long-term average. On 16 September Thames Water put London's reservoir storage at 59%, against a seasonal average of 78%.
Demand rose as supply fell
In July 2026 demand in London ran 7% above normal. Between 70% and 80% of the city's water is taken from the Thames and the Lee into reservoirs, which hold 165,000 Ml in west London and 37,000 Ml in the Lee Valley. Groundwater in south east London adds up to around 300 Ml/d.
A small backstop
London's desalination plant at Beckton now carries a planning value of 100 Ml/d, down from 150 Ml/d, and produced at most 46 Ml/d in 2024 test runs. The dry ground also hit the pipes: trunk main bursts across Thames Water's network rose from 60 to 106 in 2025/26.
No new source before 2033
The schemes meant to add supply for London are still awaiting planning consent, and the first is not planned to operate until 2033. Until then, the city's protection in a long drought rests on restrictions and on cutting demand.
Who supplies water in each part of London, what households pay in 2026/27, where Thames Water's finances and recapitalisation stand, and which decisions to watch over the next year are set out in the full profile.
The full report, London City Intelligence Profile, is available for USD 99 at https://ourfuturewaterintelligence.com/reports/london-city-intelligence-profile. For a free overview, see https://ourfuturewaterintelligence.com/cities/london.