A Guardian investigation has found that some of England's largest businesses use billions of litres of water a day from the public supply with little transparency or obligation to cut consumption, even as millions of households face hosepipe bans and three-quarters of the country experiences drought. Companies use 2.6bn litres daily from the public network, accounting for roughly 30% of total public supply use, with two-thirds of that consumption occurring in areas already classified as water-stressed. Regulators say a combination of poor data and "commercial secrecy" is hampering efforts to monitor and manage industrial demand.

The investigation identifies oil refineries, chemical plants and paper mills as among the heaviest users, with the site of ExxonMobil's Esso refinery at Fawley, near Southampton, ranked as the largest single user of public water supply, though other operators also draw from that site. ExxonMobil disputed the figures, citing commercial confidentiality, and Mosl, which runs the business water market, said it would seek to redact parts of related evidence submitted to a House of Lords committee. The picture is complicated by patchy metering — one in ten businesses are unmetered, and only 11% of metered businesses have smart meters — while data-sharing restrictions mean even government bodies such as Defra and the Environment Agency must negotiate bespoke agreements for access. The Environment Agency and Ofwat are now pushing for mandatory reporting of current and projected business water use to strengthen national water security planning.