Surrey gardens and roads flooded with sewage after overspill at treatment plant leaves ‘boggy’ smell

Contaminated water flooded Lee Street on Wednesday (November 27) and tumbled down into people’s gardens, leaving some residents almost housebound. Steve Pelham, who has lived in his house for six years, said he had to “wade through” metres of contaminated water to leave his property.

A Thames Water spokesperson said: “We are sorry to residents impacted by a hydraulic pump issue at our Horley Sewage Treatment Works.” They added the pump has now been fixed and teams are engaging with local residents to clean up the area.

It is not the first time the gardens have been flooded, Mr Pelham said: “This time I’m not going to let them get away.” He said it was a “carbon copy” of when the plant flooded in 2019 and it is “not acceptable” that it has happened again.

“It is not nice as all our possessions that have been flooded have to be thrown away,” Mr Pelham told the Local Democracy Reporting Service (LDRS).

The Horley treatment plant is just about 200-300 metres away from Lee Street. Mr Pelham said he is worried his house could be “unsaleable” with the flood risk potentially “devaluing” the property.

Cllr Steve Wotton (Horley West and Sidlow/ Liberal Democrat) tested the mysterious liquid and found high concentrations of phosphate and ammonia which “strongly indicates” the presence of sewage.

Chris Coghlan, MP for Dorking and Horley, visited Mr Pelham and said: “It is completely outrageous that this keeps happening and putting my constituents’ health at risk. It is deeply upsetting that this situation continues.”

Mr Coghlan said he has been campaigning with Cllr Wotton for years to upgrade the sewage plant. The Lib Dem MP added he is going to “keep putting pressure on Thames Water” by writing to the CEO and the Environmental Agency to resolve the issue.

A Thames Water spokesperson said: “”We have clear and deliverable plans to upgrade 250 of our sites across the region, to increase treatment capacity and reduce the number of storm discharges. This includes our site at Horley.

“As infrastructure ages and demand on it increases, more investment is needed across the entire sector. That’s why we’ve asked for increased investment in the next regulatory cycle between 2025-2030.”