Toilets, baths, washing machines and sinks no longer empty into the River Wandle after 15 months of hard graft by Thames Water and the Environment Agency.

In 2014 extensive detective work began in the area after dirty water, which should have gone into sewer pipes and the local treatment works, was found to be running into drains meant only for surface water and then out into the Wandle.

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 412 homes in the Morden area.

Investigators used CCTV, dye, household surveys and wire traps set inside drains to trace the problem to 17 homes which were found to be connected to the wrong pipes.

A total of 40 household appliances (including three toilets) were found to be emptying straight into the watercourse.

Thames Water then worked with home owners to make sure their pipes were properly reconnected.

Kate McDermott, environment officer at the Environment Agency, said: "The Environment Agency is really pleased that Thames Water’s hard work has helped clean up the flow of wastewater to the river. Washing machines, showers and toilets were regularly discharging into the watercourse and reducing the water quality for the wildlife and creating an unpleasant environment in the river.

"To ensure that this doesn’t happen again in the future we encourage homeowners to check that they are connected right - you can find information on how to do this on the ConnectRight website ("

Brighid Heaney, from Thames Water’s environment team, said: "No one wants toilets emptying directing into their local river so it’s a great feeling to have sorted this problem out and improved the water quality in the stream. 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."