Thames Water fined after pumping undiluted sewage into River Mole

A two-day sentencing hearing at Lewes Crown Court was told there was a “significant and lengthy” period of polluting the Gatwick Stream and River Mole between Crawley in West Sussex and Horley in Surrey on October 11 2017.

Judge Christine Laing KC said on Tuesday that said she believed Thames Water had shown a “deliberate attempt” to mislead the Environment Agency over the incident, such as by omitting water readings and submitting a report to the regulator denying responsibility.

Thames Water had pleaded guilty on February 28 to four charges relating to illegally discharging waste in October 2017, but had denied seeking to mislead the Environment Agency in the events, instead arguing “significant errors were made.”.

The court heard how a storm pump unexpectedly activated and was filling up the storm tank, despite no substantial rainfall, for 21 hours which went unnoticed.

On October 11, 2017, the pump then began spilling the sewage into the river for an estimated six hours. The court heard how no specific alarms to alert staff to the overspill, or how long the undiluted sewage was entering the tank, was in place.

When an alarm was heard, the lead technician was uncontactable as they were awaiting a new mobile phone.

Judge Laing KC said she found it “utterly extraordinary” that environmental disasters can occur because of issues such as this.

Addressing the biggest water company which has had 20 previous fines for pollution spillage, including the biggest record fine to date six months prior to this incident, Judge Laing KC added: “They should have put in every effort into tidying up the problem areas.”

This penalty comes as the water firm, which serves 15 million households across London and Thames Valley, faces concerns over its future amid mounting debt.

Thames Water’s chief executive Sarah Bentley stepped down with immediate effect last week after she gave up her bonus due to the company’s environmental performance.

The record fine against a water company for illegal discharge of sewage is held by Southern Water at £90 million for nearly 7,000 incidents across Hampshire, Kent and Sussex in a case brought by the Environment Agency in 2021.