A water company has been slated for “marking its own homework” incorrectly after falsely reporting a 100-hour sewage discharge.

Campaigners flagged Southern Water’s delay to properly record the incident off Whitstable before stating they should not have to be “doing their work for them”.

The incident prevented swimmers going into the water due to concerns over the outflows going into the sea.

Southern Water’s River & Seas Watch - an online tool to monitor sewage discharge into water - reported four ongoing sewage releases of more than 100 hours on Monday, October 27 in the Whitstable area, according to campaigners.

The water company later confirmed this was a false alarm caused by an “unfortunate combination of configuration changes and the impact of Storm Benjamin” sparking an IT fault on October 23, which was rectified later that day.

The company was then forced to manually override the records from the 100-hour readings.

But campaigners say the backlog to update the system stopped many from going swimming over the previous weekend.

SOS Whitstable, a campaign group formed in response to Southern Water’s historic poor performance relating to sewage releases, has criticised the water company after members flagged the issue.

The group says Southern Water later confirmed the reported 100-hour sewage release data was incorrect and there had in fact been ones lasting 17 minutes, 20 minutes, 2 hours 11 minutes, and one "not-genuine” 58-minute event.

There were also more than 32 hours of actual releases on October 22 and 23.

Water companies are allowed to release sewage into the ocean when it rains heavily or during storms to prevent overflows in the system which could lead to the sewage instead backing up into people’s homes.

But in recent years the release of sewage into the sea, rivers and lakes have made the UK’s privatised water system the object of controversy and political attention.

Southern Water is the private water company which manages the water and sewerage system across a large part of the east and north Kent coast.

The firm has attracted significant controversy in recent years due to regular discharges of sewage into the sea, especially in the Whitstable area.

Some residents have even persistently refused to pay their water bills in protest against the company, which led to retired magistrate Chris Stanley being forced to stump up in court in June.

Bryony Carter, founding member and director of SOS Whitstable, said: “We swim all the time, so we all monitor it as much as possible.

“The whole of the weekend it was showing that there was a 100-hour pollution incident and obviously we didn’t go swimming for that reason.

“We’re losing out on amenities because of the wrong reporting – don’t get me wrong I'm happy it wasn’t 100 hours.

“It’s just an example of why it shouldn’t be sitting with them isn’t it – it needs to be brought back into public ownership.

“We seem to be doing the work for them so it may as well come back to us to complete it.

“They’re self-reporting, which is like marking their own homework, and they're not even doing it correctly.

‘They’re self-reporting, which is like marking their own homework, and they're not even doing it correctly…’

"It shouldn't be up to the public to realise something is wrong.”

“It’s a disaster basically, people are relying on that information to go swimming.

“If the integrity of the information is not valid it makes you think what else are they modifying.”

She also argued that mistakes like this could harm tourism to the area.

But the company has singled out accusations of “marking its own homework” as unfair due to the firm being forced to abide by strict reporting rules saying such claims should be referred to the industry’s regulator.

A spokesperson for Southern Water said: “A technical fault temporarily affected our Rivers and Seas Watch platform, which provides near real-time information about storm overflow activity.

“For a short period, data did not show properly. This issue was quickly fixed but led to a backlog which had to be manually corrected.

“We wrote to all key stakeholders about the problem and are sorry for any confusion and concern caused.

“We are investigating what happened to minimise any risk of a repeat.

“Our rollout of spill monitors and approach to publishing storm overflow data openly has been industry leading – but we are also committed to continual improvement of this service, with further upgrades planned for 2026.”

Campaigners say the monitoring of the outflow at Tankerton Circus has malfunctioned regularly, but in January, Southern Water says it installed the most up to date monitoring technology there following complaints.

The company also stressed this most recent fault is novel and is being investigated.