A pilot scheme in west London will fund a dedicated council officer to tackle "misconnections", where households wrongly plumbed into surface drains send raw sewage directly into rivers instead of the sewer system. The trial, backed by the mayor of London's office, targets areas including the River Brent catchment, and could be extended across the capital if successful; campaigners say misconnections may be the single biggest cause of pollution in London's rivers, and are urging councils to use their existing enforcement powers more forcefully.

A freedom of information request by Friends of the River Crane Environment found that in October 2024 seven blocks of flats in north and west London, affecting at least 100 homes, were discharging waste into the Crane and Brent rivers; Thames Water says only three of these, in Ealing, have since been fixed, with two problem sites remaining in each of Barnet and Harrow. The initiative forms part of a 10-year plan announced by Sir Sadiq Khan to clean up ten London waterways, backed by £1.8bn from water companies, boroughs and charities, plus £2.7m from the mayor over three years on top of £13.6m already pledged. Thames Water said misconnections are usually accidental but remain the property owner's responsibility, while Barnet Council said such cases can be complex to resolve.