Position on Misconnections – by the Catchment Partnerships in London Group

The Catchment Partnerships in London Group

Position of the Partnership Hosts on Misconnections

The Catchment Partnerships in London Group (CPiL) consists of the River Catchment hosting organisations operating wholly or partly within Greater London. The purpose of the group is to support the work of the partnerships including sharing lessons and experiences to help achieve a coordinated approach to delivering cleaner rivers and Water Framework Objectives. This Position Statement is supported by the following organisations –       

This position statement is supported by the above organisations.

 Due to misconnected domestic drains, foul water is discharging directly into rivers across London.  As a result, pollution is killing wildlife, damaging ecosystems, risking human health and turning rivers and streams into ‘no-go’ areas.  The Catchment Partnerships in London call for increased attention, action and investment to tackle this unacceptable situation.

  1. Misconnections in London

Investigations by Thames Water (TW) suggest that 3% of properties in London are misconnected to allow foul water to discharge into the rainwater system, and in some areas the misconnection rate may be significantly higher.  Three percent of the total number of households in London is 98,000 and when it is taken into account that a property may contain a number of households, the scale of the problem is clear.

In addition, there are problems caused by rainwater drains wrongly connected into the sewerage system, resulting in sewage treatment facilities being overwhelmed.

The pollution which enters London’s rivers as a result of misconnections is causing chronic damage to the health of our rivers. For instance concentrations of ammoniacal nitrogen, derived from misconnected toilets and cross connected drainage systems, have been shown to be as high as 14.9 mg/l at the outfall, which is the source of the Glenn Brook (Lea Catchment) and 4.82 mg/l in the upper Yeading Brook (Crane Catchment). The Water Framework Directive (WFD) sets an upper limit of 0.6 mg/l ammoniacal nitrogen in our rivers – while a level of  0.2mg/l will start to harm fish (depending on species).

In addition to causing ecological damage to our rivers, there is a risk to human health from e-coli and a gradual degradation of the value of our important urban green spaces. Rivers that run through these spaces often become unsightly and start to smell like sewers.

  1. Management measures

Two hundred Polluted Surface Water Outfalls (PSWOs) have been approved for investigation and resolution in TW’s Asset Management Period 6, 2015-2020, as identified by the Environment Agency (EA). Remediating misconnections has proven to deliver water quality improvements within rivers. However, it is unknown if rectifying this number of PSWOs over 5 years will, in the long term, effectively tackle the scale of the problem in London’s Rivers.

CPiL position – CPiL wants to see systematic, routine inspection and analysis of the quality of water flowing out of surface water outfalls in London in order to gauge the extent of this issue and assess if the current management measures are appropriate.

CPiL action – CPiL will support EA and TW by gathering evidence on the scale of the problem.

  1. Current Method of detecting a PSWO

Currently we rely on informed members of the public reporting a problem at an outfall to the EA pollution incident line (0800 807060). However it is clear that by this stage, it is too late. Pollution is already damaging the river and its wildlife. There is a need for a nationwide, systematic method for the detection of incorrect plumbing in order to get the issue under routine surveillance and start to bring it under control.

CPiL’s position – CPiL advocates a change in the law so that property owners are obliged to undertake a drainage survey, including an inspection for misconnections, during the sale of a property.

Changes to properties involving additional plumbing work, such as building extensions, should also be inspected.

CPiL action – CPiL members will lobby for the above change in the law.  Members will also lobby for the issue of building extension inspections to be raised up the agenda.

  1. Resolution of Misconnections

The resolution procedures for misconnections could be considerably improved. Currently once a building has been identified as misconnected, the local water company informs the building owner and asks them to resolve the issue. However should no action be taken, the details are handed over to the Local Authority, which  takes enforcement action through the Building Regulations Act 1984. Some Local Authorities undertake this task fully while others do not, depending upon local priorities.

The Chartered Institute of Environmental Health, the ‘professional voice for environmental health’, who ‘provide information, evidence and policy advice to local and national government, environmental and public health practitioners in the public and private sector’ dispute this reading of the buildings act and believe that the Environment Agency have powers of enforcement for misconnections. This situation highlights the need for clarification and reform of the enforcement procedures.

DEFRA have recently proposed a consultation on giving powers of enforcement to the water companies. All water companies have stated that they would welcome these powers but as yet DEFRA have not set a timeline for the consultation.

CPiL recognises that there may be issues with handing enforcement powers to private companies, however the current procedures could be significantly improved if a single organisation, public or private, were given powers of enforcement.

CPiL’s position – CPiL wants to see DEFRA set a date for the consultation on enforcement of misconnections and wants its members and the National Catchment Based Approach(CABA) river groups consulted on the wording of the consultation

CPiL’s position – The current procedures for enforcement of Misconnections are not clear or effective and should be handed to a single organisation, either public or private.

CPiL’s action – CPiL will lobby for the above.

  1. Public Awareness

Research by Ipsos Mori and others highlights very low levels of awareness about duel drainage systems, and the environmental problems caused by incorrectly plumbing domestic appliances into the surface drains. Catchment Partnerships, with the engagement of grass roots organisations, are very well placed to support the EA and water companies in raising awareness of misconnections issues at a local level.

CPiL position – CPiL members wish to see greater public awareness campaigns on the issue of misconnections and more resources put into communicating the issue with pertinent groups such as plumbers, housing partnerships and environmental health officers.

CPiL’s action – CPiL Partners will work to raise awareness of the issue across London and support the Connect Right campaign, the Water Safe Approved Plumber scheme and Yellowfish Campaign.


The Catchment Partnerships in London Group: Host contacts for further information –

Joe Pecorelli, ZSL:   Joe.pecorelli@zsl.org

John Bryden, Thames21:  07968 012828 john.bryden@thames21.org.uk