During the past four years Thames Water, together with the Environment Agency, has traced 410 misconnections into Mayes brook – but  predict there are at least another 60,000 misconnections still to be found.

In 2010 extensive detective work began in Dagenham after dirty water, which should have been destined for sewer pipes and the local treatment works, was found to be running into drains meant only for surface water (rainwater from homes) and then out into the brook, a tributary of the River Roding.

The Environment Agency suspected that houses had incorrectly connected their wastewater pipes (for dirty water from appliances like toilets and showers) into the surface water pipe network, prompting an investigation by Thames Water into 10,000 homes north of Mayesbrook Park and up to the A12.

An astonishing 410 homes were found to be connected to the wrong pipes, and by the close of the investigation in April 2014, 860 household appliances (including 23 toilets) were found to be emptying straight into the brook, which meanders through Mayesbrook Park.

Following the successful identification of the problem properties, Thames Water worked with home owners to make sure their pipes were properly reconnected . As a result  231 washing machines no longer empty their loads into the Mayes Brook.

Brighid Rowan, from Thames Water’s environment team, said:

“No one wants toilets emptying directly into their local river so it’s a great feeling to have sorted this problem out and improved the water quality in the brook. Thankfully recent Environment Agency reports show pollution levels have significantly reduced.”

“We’ve got a massive job still to do to trace more of these misconnections across our patch – so it’s really important that anyone having extensions built or carrying out plumbing work employs a reputable plumber and knows exactly where their wastewater is heading.”

Initial investigations to identify problem areas involved the Thames Water team hanging wire cages inside the drain network to catch toilet and kitchen waste and other evidence of pollution as it was flushed out of toilets and taps and along to the watercourse.

Once the hotspots were identified further detective work was carried out, including household surveys, CCTV surveys and placing colourful dye into toilets to trace where it flushed.

In the Thames Water region, plumbing mistakes result in up to one in 10 households misconnecting their waste appliances to the surface water system - the equivalent of almost two Olympic-size swimming pools of wastewater wrongly entering the region’s rivers and streams every day.

The Thames Water misconnections team work in close partnership with the Environment Agency to trace and reduce the number of misconnections, but it is predicted that there are at least another 60,000 misconnections still to be found.