Sewerage network

We treat 863 million litres of sewage from 2.8 million customers every day.

We have:

Sewage flooding

Sewage flooding is rare but when it does occur it can be devastating so tackling it remains a key objective.

The number of sewer flooding incidents was 1.16 incidents per 10,000 properties in 2019-20 compared to our target of 1.66.

We were ahead of our target as a result of:

• our campaigns about the problems caused by flushing wet wipes down 
  toilets
• explaining the issues caused by pouring fat down sinks
• planned operational maintenance 
• the generally dry weather conditions in the region last year. 

As most flooding incidents occur due to blockages caused by inappropriate substances poured down the sink (such as fat) or flushed down the toilet (such as wet wipes), we continue to focus on customer awareness and information. 

We continue to work hard to improve our monitoring and maintenance of our sewers and worked with customers to reduce the amount of sewer misuse that can cause blockages through the flushing of wet wipes, or disposal of fats, oils and greases down the sink.

A new framework is being developed for all water companies to give visibility of long-term sewerage plans.

It is an ambitious framework which we are embracing, requiring drainage and sewage management plans to be published by 2023.

Several locations in our region with water bearing chalk strata can be affected by high groundwater levels which infiltrate the sewer network and restrict toilet use. 

It is a complicated issue so to help customers understand it and help prevent it, we produced a computer-generated animation explaining ‘How groundwater can cause sewer flooding’.

Infiltration reduction plans

Our infiltration reduction plans continue to reduce the risk of groundwater entering sewers and drains. We proactively inspected more than 100 km of sewers for signs of infiltration and permanently sealed 6.1 km of sewers where seepage was occurring.