More than 200 tankers of raw sewage were driven to a Surrey town and left there for six months, causing a “nightmare” for residents after all of Thames Water’s 360 treatment plants reached critical capacity.
Thames Water has apologised but is refusing a request from Surrey councillors to make a financial acknowledgement to the community by reducing bills for 11,000 people.
The crisis in treatment capacity began last February when Hogsmill, one of the main Thames Water treatment works, broke down, forcing staff to move thousands of cubic metres of raw sewage at speed and deposit the contents into tanks in Camberley because there was no other storage capacity across its whole estate. Storage tanks at Woking were already full from a previous crisis.
Thames Water has told councillors in Surrey it had had no choice. Either they moved the sewage to storage tanks in Camberley, emptied it into rivers causing massive pollution, or left it in tankers on the roadside which could have exploded, causing a major national incident.
Evidence of the crisis across Thames Water’s whole region comes as MPs have recalled the chief executive officer to answer questions on Tuesday on the company’s financial situation.
Auditors have warned the parent company of Thames Water it could run out of money by April if shareholders do not inject more cash.
In the incident, which took place over the summer, 6,000 cubic metres of raw sewage sludge were left in an open tank for six months without being treated. About 11,000 residents suffered the impacts of raw sewage being stored during the hottest summer on record. Odour suppression was put in place but only during the day and it did not cover the entire tank.
Thames Water was called to explain why it had decided to move so much sewage to the town. In evidence, a manager said they had no choice.
“The risk that we had if we didn’t move that sludge was pollution of the waterways and potentially 30-40 trucks parked on the motorway in the middle of summer which could have exploded,” he told the external partnerships committee of Surrey Heath borough council.
The Liberal Democrat-led council is demanding compensation to the 11,000 residents who suffered the impact of the raw sewage held in open tanks at Camberley sewage works for six months during the hottest summer on record.
Councillor Rob Lee, who chairs the external partnerships committee, said Thames Water had offered and then withdrawn an offer of £60,000 for a community playground as a conciliatory gesture.
He said: “They left this sewage in an open tank until August, and only used odour suppression control in the daytime.
“Moving these tankers of sewage to Camberley to be stored saved the company millions in terms of fines they would have faced if they had polluted the waterways and it stopped a potentially major national incident of tankers exploding by the roadside.
“It clearly saved Thames Water in material terms potentially millions, if not tens of millions of pounds. We believe these 11,000 residents should be compensated by being offered 12 months complimentary water bills as a gesture of good will.”
The Hogsmill treatment works in Surbiton, Surrey has had frequent problems. In 2021, Thames Water was fined £4m after a catastrophic incident at the works when untreated sewage escaped from sewers below London into a park and a river.
James Bentley, the operations director for Thames, told councillors: “We didn’t get everything right in that process and we’re not here to pretend that we did.”
“The residents had to endure something for too long that was unacceptable. I have been asked to consider some form of financial acknowledgement, I took that consideration to my leadership and I am not authorised to say I will reverse their decision.”
There has been a change in the permits at Camberley to stop the storage tanks being used again. Councillor Lisa Finan-Cooke said: “What is going to happen going forward?”
The company said there was now a formal signoff process if they wanted to use strategic storage tanks.
A Thames Water spokesperson said: “We apologise for the impact this emergency storage of sludge has had on the residents of the area near Camberley sewage works. We should have communicated more proactively with residents and responded better to the understandable concerns that were raised. We have learned from this situation and are pleased to say that this site will no longer be used for such emergency sludge operations.”
