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Operation Streamclean

A 5 year plan to combat the menace of streams polluted with sewage

Operation Streamclean is a venture set-up and funded by Wessex Water with the aim of reducing sewage pollution entering streams and watercourses.  Equipped with a CCTV camera, a high-pressure water jetter to clear blockages, dye testing and sampling equipment, the team respond to calls about polluted watercourses and track down the pollutant’s source.

August 2006 - Operation Streamclean's success at Coy Pond Gardens [more]



The job of policing the nations rivers and watercourses rests with the Environment Agency.  The Agency regulates, controls and monitors all known point discharges.  However, pollution entering these waters by means of diffuse, irregular or intermittent sources is much more difficult to identify.  This diffuse pollution in urban areas is very likely to be of sewerage origin.  Wessex Water is responsible for all of the foul and surface water public sewers in the Wessex Region and has recognised its responsibility towards pollution prevention by setting up Operation Streamclean, which builds on many techniques of environmental protection, from solar power to skip hire London companies offering recycling skips. The purpose of Operation Streamclean is to investigate, identify and reduce the incidences of pollution of surface waters by sewage.



The first Streamclean venture was set up in Bristol in 1992 where it was responsible for major reductions in the frequency and volumes of sewage polluting several local streams.  The present operation now covers the whole of the Wessex region.  There are two teams of two operators, each fully equipped (including CCTV equipment) to investigate sewers, chambers, manholes, pumping stations and streams etc.   They are supervised by a lead operator based in Poole and are managed by the Sewerage Manager.  They have a functional link to scientists who can direct and interpret their investigations. This organisational flexibility allows them to call upon experienced local engineers, sewerage teams and scientists as the need arises.



The Streamclean teams work closely with the Environment Agency and Environmental Health Officers in arriving at priority areas for investigation.  

The teams use local knowledge, GIS mapping, surveys, sampling and analysis and in-sewer monitoring techniques to pinpoint the cause of a pollution.  

Once identified, enforcement of remedial measures is organised by the Streamclean manager.  

Responsibility for enforcement could lie with the Environment Agency (who have certain powers to prevent pollution), with Environmental Health under the Building Regulations or with other statutory agencies like Highways departments.  

In some circumstances, where there is no clear responsibility, Wessex Water has directly organised the remedial work.

What does Operation Streamclean look for?


Most homes built in the past 30 years have ‘separate’ drains, with two drainage systems:

1. the foul sewer, carries dirty water to a sewage treatment works where it is treated before it is discharged to a river;

2. the surface water drain, carries clean water directly to a river or soak-away, as do most road drains.

Wrong connections occur when toilets, washing machines, dishwashers, baths, and showers are connected by mistake to the surface water drain.  This often happens when an extension is built, or when a new appliance is installed and sometimes when a new house is built and the builder connects to the wrong drain.  Any discharge to the surface water drain will pass untreated into a stream or soak-away and will cause pollution.  In a stream, this will cause unpleasant smells and unhealthy conditions where plants and fish will not survive.  If the pollution enters a bathing water (e.g. via the Bourne Stream) it can affect a blue flag area and make bathing or paddling unsafe.

The Operation Streamclean teams are particularly looking for wrong connections.

Visit the Water Pollution Guide, for information about the sources of water pollution and how they can be treated, and the potential danger pollution causes.

Work carried out in the Bourne Stream catchment


The Operation Streamclean team has been investigating incidents in the Bourne Stream catchment since April 2002:


Domestic Waste Checks

Our Streamclean team has nearly finished domestic waste inspections; 63 done, 20 to go.  The purpose of the inspection is to check for misconnections to surface water that will flow into the Bourne Stream.  We have only checked premises where we have received a request from the householder.  At each house we check the drainage from household appliances, sinks, baths, showers, toilets and roofs.  We look for proper connection to foul and surface water drains and for the presence of a septic tanks or soak-away.

All of the properties we checked were correctly connected to foul or surface water sewers.  Nearly all of the properties had a garden soak-away for their roof water, which is good news for the Bourne stream. None of the properties had septic tanks.  As long as water from driveways etc does not drain to the public surface-water sewer, householders with a soak-away will be eligible for a reduction in their sewerage bill from Wessex Water.  Property owners have been notified of our findings and have been left a form to complete if they wish to make a claim.

Whilst conducting the surveys, we stumbled upon a more recent property that had all of its foul drainage passing to surface water (and hence the Bourne Stream).  This was passed to Borough of Poole to action.  

Other successes have included:

Lower Gardens

Sand from a local building project

Surrey Road

Private sewer spilling to road gullys and the stream eliminated by a new sewer connection

Cambridge Road

Sand from a local building project


Combined sewer overflow investigated

Prince of Wales Road

Combined sewer overflow investigated

Braidley Road

Surface water drainage investigated

Coy Pond

Blockages due to sewer collapse (now repaired)


Foul drainage from a local school

Prince of Wales Road

Surface water sewer misconnections from new build properties in the area

Coy Pond Gardens

Surface water sewer fractures identified at manufacturing company premises; all discharges now redirected to their foul sewer.

Coy Pond Gardens

Sand and rusty discharge from old pipes being removed from a local development site

Coy Pond Gardens

Local company identified cleaning operational equipment over surface water drains on a weekly basis; advised of impacts and have agreed to stop [more]

Coy Pond Gardens

Local company identified cleaning down manufacturing equipment with contaminated waste water flowing to surface water drainage; advised of impacts and immediately installed bunds to prevent a re-occurrence

Compiled By: Mike Robinson, Divisional Scientist, Wessex Water

Last Update: August 2006

Streamclean cleans up in Dorset (Press Release August 2006)

In addition, the team is currently monitoring five key sites for indicators of sewage pollution.  The Streamclean crews were also used to spearhead the investigation of householder premises for wrong connections during the ‘Use Water Wisely’ campaign organised by Sembcorp Bournemouth Water.

Wessex Water has also compiled a database of all 62 permanent discharges to the Bourne Stream and assessed the pollution risk from each of them.

What YOU can do

If you have an older house with a combined drainage system you cannot have a wrong connection because all of the water from your house is collected in one sewer and flows to a sewage treatment plant. 

If you have a separate system:


Please don’t ...

Do ...

Connect waste pipes from toilets, showers, baths, sinks and water using appliances into roof-water down-pipes or gullies

Ask your local council for advice when connecting a waste pipe to a drain.


Ignore existing wrong connections.


Check your existing drains.  If you find a wrong connection, put it right.

Dispose of oil, garden or household chemicals or cleaning waste (especially bleach) down any open drain, into gutters or onto the garden.

Ensure that when you buy a house there are no wrong connections.  Ask your surveyor to include this on the report.

More surface water pollution solutions

Finally, if all of the roof water from your property drains to a soak-away and your driveway or patio does not drain onto the highway, you may be eligible to a reduction in your Sewerage Bill from Wessex Water.  

Telephone the surface water drainage line: 0845 601 5982 (24 hours) for an application form.


Blocked Drains


Blocked drains can cause a spill of sewage to a highway or garden.  In the hilly areas of Bournemouth and Poole this will quickly pollute a surface water drain and/or a stream and maybe even the Bourne Stream and your local beach.


Having a blocked drain is a smelly and sometimes expensive business, but Wessex Water may be able to help you.  If you think you have a blocked drain, please call us first so we can check whether it is a blockage in a public sewer or a private drain.  This is a free service, you will not be charged.  If the blockage is in a public sewer we will deal with it free of charge.  If the blockage occurs in a private drain or sewer, you and possibly your neighbours, are responsible for clearing it.  Wessex Water offers a private drain clearance service at competitive rates.  Contact us on 0845 600 4 600 (24 hours).


Contact Wessex Water on 0845 600 4 600 (24 hours)

Visit our web site on www.wessexwater.co.uk


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