Rivers: Sewage

Question

It is difficult to quantify how much sewage is discharged in London and the South East through misconnections, due to the complex nature of urban drainage and the masking provided by other polluting sources.

The Environment Agency (EA) collects data on reported incidents of polluted surface water outfalls, including those attributed to misconnections. However this data cannot be considered comprehensive due to difficulties in identifying and recording incident sources and might exclude a significant number of incidents reported direct to water companies.

In 2013 a UK Water Industry Research project estimated the potential number of misconnections in each of the water company catchments and included the following estimates for water companies in London and the South East. It provides an estimate of the potential overall scale of the problem for water companies although the figures might be regarded as a conservative estimate: Anglian Water circa 24,000 misconnections, Southern Water circa 16,000 misconnections and Thames Water circa 48,000 misconnections.

The water companies, EA and local authorities are working to address misconnections and raise awareness with householders, the building trade and other professionals. This is being targeted by the ConnectRight campaign and the trade accreditation scheme, WaterSafe.

This work is being co-ordinated by the National Misconnections Strategy Group which in addition to the organisations named above includes Defra and the Consumer Council for Water. The group has also developed good practice for the industry, as well as looking at measures to limit misconnections being made in the first place.

Further work to limit and reduce misconnections is also being planned as part of the planning for the next water company investment round in the period 2020 to 2025 to maintain a resilient wastewater and drainage system.