New developments in England will soon have to include sustainable drainage – including grassy areas, wetlands and permeable surfaces – to curb flooding and pollution. The government is expected to make such features mandatory from 2024, with the goal of reducing surface flooding and relieving pressure on traditional sewerage systems.

New developments often increase flood risk by covering previously permeable surfaces, meaning that sewers can become overwhelmed during periods of heavy rain. In some cases, this leads to the release of untreated sewage into rivers and oceans.

Alongside reducing the build-up of surface water, sustainable drainage measures can create habitats for wildlife and enable water to be reused.