Question to the Department for Environment, Food and Rural Affairs:

To ask the Secretary of State for Environment, Food and Rural Affairs, whether he has made an estimate of the number of homes affected by sewage rising into (a) gardens, (b) toilets and (c) sinks after heavy rains.

Discover Water, a water company performance data website which brings robust already-available company data from a range of sources together includes detail on sewer flooding incidents. In 2022-23; 47,176 areas of private land or gardens were flooded by sewage and 4,794 properties were internally flooded by sewage.

Sewer flooding may occur for a number of reasons, including a failure of the sewerage system; blockages; or when the sewerage system is overwhelmed when too much rainwater enters the sewers from surrounding roads, houses and land. Storm overflows stop sewage backing up into homes by releasing wastewater when the system is overwhelmed during periods of heavy rain. A growing population and ageing infrastructure, means these storm overflows are being pushed beyond their intended limits and that needs to change. As part of our Plan for Water, water companies are delivering the largest infrastructure programme in history - £60 billion of investment over 25 years. We continue to hold water companies to account and will not hesitate to act where there is evidence of wrongdoing.

Government recognises the importance of having a robust drainage system both now and for future demand. As per commitments in the Environmental Improvement Plan and the Plan for Water, Defra will legislate to require water companies in England to produce Drainage and Wastewater Management Plans (DWMPs). DWMPs set out how a water company intends to improve their drainage and wastewater systems over the next 25 years, accounting for factors including growing population and changing environmental circumstances. When producing DWMPs, water companies will be required to identify solutions in collaboration with other partners such as lead local flood authorities (LLFAs) and other flood risk management authorities.

Flooding from heavy rain and thunderstorms is known as surface water flooding. In England 3.4 million properties are at risk of such flooding. The responsibility for managing local flood risk, including from surface water, falls to LLFAs, in partnership with highways authorities and water companies. LLFAs are required to identify and agree local objectives for managing these local flood risks and to set them out in their statutory Local Flood Risk Management Strategy.