The largest water reuse system in the UK, which could save thousands of litres of water a day for people living in one of the driest regions of the country, is not allowed to be switched on because of drinking water regulations. As water supplies in England reach critical levels, the Guardian can reveal that a model water recycling system within an urban housing development in Cambridgeshire has not been switched on since it was made ready in 2021. Thousands of residents could be saving about 25 litres per person per day by using recycled rainwater in their homes for non-drinking purposes.
But the water reuse system – installed by Cambridge Water at the Eddington urban quarter, a mixed development of housing, student accommodation, academic research space and a primary school and nursery – has been switched off because the Drinking Water Inspectorate (DWI) deems it is not in line with the law. This summer’s drought has led to Cambridge Water and neighbouring Anglian Water imposing hosepipe bans as reservoirs have run low. The block to the water reuse scheme, and others that water companies want to install, is hampering attempts to bring in large-scale water recycling schemes for new developments and tackle the extreme water shortages the country faces by 2055, experts warn.
Despite ministers in the current and previous governments being aware of the obstacle, there has been no change to the law and the reuse system remains locked down. Lutz Johnen, the chair of the UK Water Reuse Association, said the block at Eddington needed to be removed urgently and the system copied at scale across the country. But they need to act urgently.
We are running out of water, we are seeing that this summer, water companies are struggling,” he said. The UK is lagging behind.” Water reuse involves either rainwater harvesting or recycling grey water from household appliances, or both, for domestic and commercial buildings. In homes it can save 20 to 25 litres of water per person per day.
Other countries in Europe, such as Belgium and Germany, have had reuse systems operating for more than 20 years. In Belgium, mains water use is about 90 litres per person per day, compared with 140 litres per person per day in England and Wales. At Eddington, on the north-western edge of Cambridge, the urban quarter developed by Cambridge University will eventually provide homes for 8,000 people.
Its state-of-the-art water recycling system involves swales that capture rainwater and feed it into a lagoon that protects nearby brooks from flooding. Cambridge Water designed a treatment system that allows the lagoon’s water to be recycled back into the homes for toilet flushing and other non-drinking purposes, with the aim of significantly reducing water consumption to about 80 litres per person per day. But the DWI intervened to object, saying water companies providing grey water in homes was illegal, according to its interpretation of the 1991 Water Act.
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