About the Drainage and wastewater management plan

Why develop a DWMP

We are publishing our drainage and wastewater management plan (DWMP) to show how we are addressing pressures on our drainage and wastewater systems for current and future risks.

Climate change, population growth, increases in awareness of storm overflows, tightening environmental standards and changes in customer behaviours and expectations are putting increased pressures on the water sector.

We have a privileged status as a provider of essential sewerage service to around three million customers and to protect the highly sensitive environment within the Wessex area.

We are proud of our historical industry leading performance for customers, our communities and the environment, and we believe we should be an exemplar to the industry of the future, trusted to leave the environment in a better condition for future generations, while keeping our services affordable and satisfying for customers. 

What is a DWMP

The DWMP framework was developed by the water industry and key stakeholders to provide a consistent approach across water companies for long-term sewerage planning.

It identifies how we will extend, improve and maintain a robust and resilient drainage and wastewater system in light of the current pressures on the industry.

Our strategic plan sets out the required level of investment required to achieve our outcomes, such as having an effective sewerage system and high-quality water.

Working with partners

Throughout the development of the DWMP, we have been engaging with numerous stakeholders, including customers, regulators (Environment Agency and Ofwat), catchment partners and flood risk management authorities (RMAs), such as the Lead Local Flood Authorities (LLFA).

Engagement with other RMAs is essential for DWMPs because drainage responsibilities are complex. We need to continue working in partnership with our stakeholders to find opportunities for the co-creation of water solutions to achieve efficiencies in delivering our outcomes.

Bristol Avon catchment partnership

This partnership coordinates and facilitates working together to the benefit of the water environment.

Dorset catchment partnerships

The Dorset catchment has three unique catchments: Poole Harbour, Stour and the West Dorset Rivers and Coastal Streams.

Hampshire Avon catchment partnership

Local communities and organisations have been brought together in this partnership to improve the water environment.

Somerset catchment partnership

A range of organisations have been working together since 2013 to improve the water environment.

Ricer catchments
Map of river catchments

What did our plan find?

We need to increase investment in our drainage and wastewater assets and the environment. With flooding set to increase by 50% as a result of climate change, urbanisation and development, the biggest need for investment is in storm overflows.

Our draft unconstrained plan would require more than £25 billion over the next 25 years. That’s £1 billion a year, which is significantly more than our current expenditure on drainage and wastewater enhancement.

We have therefore presented four scenarios to allow feedback during the consultation to find out which scenario our customers and stakeholders prefer.

Drainage and wastewater strategies

Find out more about our drainage and wastewater strategies within our catchment areas.

Infiltration reduction plans

Our infiltration reduction plans continue to reduce the risk of groundwater entering public and private sewers and drains.

Investing in our region

Get information and updates on sewerage investment schemes across the region.

Working to prevent blockages

Our teams are working throughout the year to prevent blockages to ensure our network operates as it should do and that waste can safely flow to our water recycling centres to be treated.

Saving water

Find out how you can save water in your home and garden

Storm Overflows

Discover the role storm overflows play in keeping areas flood free.

Treating wastewater

Find out how we treat millions of litres of waste water every day.