Flash flooding caused sewage to spill onto roads in Totton, Hampshire, on Tuesday, when a pumping station in Commercial Road became "overwhelmed" and led to a discharge.
The flooding came as pollution warnings were issued for beaches on England’s south coast after heavy rain caused untreated sewage to enter the sea.
But Southern Water said that the release is “95-95% rainwater” and should “not be described as raw sewage”.
However, environmental campaigner and music-industry businessman Feargal Sharkey, formerly the lead singer of rock band The Undertones who later had solo hits such as A Good Heart, challenged Lawrence Gosden, Southern Water’s CEO, to drink from a Combined Sewer Overflows (CSO) system.
On Twitter, Sharkey said: “Challenge for Lawrence Gosden CEO of SW, drink a glass of what comes out of a CSO, time and place of my choosing and I’ll donate £1,000 to a charity of his choosing.”
So @BBCSouthNews SW say what they dump out of sewage overflows is “95-97% rainwater”.
Challenge for Lawrence Gosden CEO of SW, drink a glass of what comes out of a CSO, time and place of my choosing and I’ll donate £1,000 to a charity of his choosing.https://t.co/9eK0DWytOo
— Feargal Sharkey (@Feargal_Sharkey) August 17, 2022
Sharkey added on Thursday: “Happy to extend that invite to Katy Taylor [Southern Water] spokesperson who appeared on [Good Morning Britain] this morning. Same rules, same donation to charity.”
In an earlier statement, Southern Water said: "We discovered that, due to intense rainfall on dry ground, the site had become overwhelmed and suffered technical difficulties.
"This led to a spill which had affected a nearby car park and roads. Specialist teams were sent to investigate, and begin a clean-up.
"We would like to apologise to nearby residents, businesses, and road users for this incident, and are working hard to establish the full circumstances to prevent a repeat."
Pollution warnings were issued this week for dozens of beaches in England and Wales after untreated sewage was discharged into the sea.
These kinds of sewage discharges are only legal in exceptional circumstances, such as after heavy rain, when there’s a risk that pipes could overflow, according to the BBC.
According to water services regulation authority Ofwat: “Storm overflows are designed to act as relief valves when the sewerage system is at risk of being overwhelmed, for example, during heavy downpours when a lot of rainwater runs into drains and the sewerage system in a short space of time.
“If the system does get overwhelmed, it can have dreadful impacts for customers, causing flooding or even backing up into people’s homes in the worst-case scenario.”
Ofwat explains that: “To prevent that happening, water companies sometimes use storm overflows to release extra rainwater and wastewater into rivers or seas. The Environment Agency and Natural Resources Wales regulate the use of storm overflows and can grant permits for them in certain circumstances.”