Four ex-employees will appear in court over allegations linked to wastewater compliance testing
Matthew Wright, the former chief executive of Southern Water, has been charged alongside three others with conspiracy to defraud.
The charges relate to allegations they were involved in a plan to manipulate water quality tests, the Environment Agency said.
The Administrative Court ruled on Wednesday the Environment Agency has the power to prosecute the former employees.
Alongside Mr Wright, the remaining defendants are Philip Barker, Clive Massey and Mark Gregory.
Following a lengthy Environment Agency investigation, charges have been brought based on evidence gathered over several years.
According to the Environment Agency, the four men are accused of conspiring to introduce artificial no‑flow events at Southern Water wastewater treatment works.
Prosecutors say the alleged scheme was intended to manipulate the Operator Self‑Monitoring (OSM) compliance testing regime and mislead both the Environment Agency and Ofwat.
According to the charges, the alleged conspiracy took place between January 1, 2012 and December 31, 2017.
The OSM system, introduced across the water industry in 2009, requires companies to collect samples from wastewater treatment works and submit the results to the regulator.
Sampling is subject to strict rules intended to ensure independence.
Operational staff should not know when samples will be taken and sampling teams must remain separate from those running the treatment works.
The Environment Agency alleges the artificial no-flow events interfered with that process.
Southern Water also faces separate charges alleging breaches of environmental permits linked to the same alleged conduct.
Five days earlier, Southern Water had been ordered to pay £7.1million in fines for separate sewage‑pollution offences in Kent.
One incident in July 2019 resulted in around 10 million litres of sewage being discharged over almost 24 hours.
The court heard the Environment Agency was not informed until the following day, preventing Thanet District Council from issuing a public warning.
Another incident during the August bank holiday in 2020 saw at least 16 million litres of sewage released over two days after a pump in Margate failed.
Southern Water was previously fined a record £90million in 2021 after admitting 6,971 unlawful sewage discharges into waters off Hampshire, Kent and Sussex.
An Environment Agency spokesman said: "We can confirm that we are taking criminal proceedings against Southern Water Services Limited and a number of former employees.
"We take our responsibility to protect the environment very seriously and will always pursue and prosecute those alleged to have committed serious offending against the environment.
