Thames Water announced a formal Temporary Use Ban on Tuesday 21 July 2026, in force from 00:01 on Thursday 23 July.
It covers the roughly 10.1 million customers Thames Water supplies with drinking water across London, the Thames Valley and the home counties. This is its whole water-supply area, rather than the postcode zones its 2025 ban used. Customers it serves for wastewater only, and customers supplied with drinking water by another company, are not affected.
Thames Water gives the cause as demand around 10 per cent above normal in the Thames Valley and home counties and 7 per cent in London, about 100 million extra litres a day, after 40 per cent of average spring rainfall and three heatwaves.
One thing to watch: reports giving an August start date, a 16 million or 29.4 million customer figure, or a Yorkshire ban following on 26 August are recycled 2022 and 2025 stories, not this ban. The 16 million figure counts wastewater-only customers, who are not restricted.