Nearly 600 million litres of sewage may have been spilt in the Medway area last year.

Medway had the second-highest number of sewage overflows and the 13th greatest number of hours of spillages in the whole south east of England.

The three Medway constituencies saw nearly 700 hours of sewage spillage over 452 instances in 2022, greater than the majority of areas in the whole south east.

No specific data is available on how much sewage was released during each spillage, however in a study of 30 treatment plants in 2020, the average output of sewage per hour for six Southern Water sites was an estimated 847,000 litres of sewage per hour.

That’s a third of an Olympic-sized swimming pool every hour overflowing into the Towns’ streets, fields, and the River Medway.

If the average from this study was repeated for the latest figures, that would amount to nearly 600 million litres of sewage overflow in 2022.

The sewage contains human waste, wet wipes and sanitary products, which pose a serious risk to the local wildlife, swimmers and others who use UK waterways.

Last year, Gillingham and Rainham had 580 hours of sewage overflow alone, with 83 hours in Rochester and Strood and 25 hours in Chatham and Aylesford.

Across the south east, badly affected areas included Chichester and Bexhill, with the worst affected area being the Isle of Wight which had almost 12,000 hours of overflow across more than 1,500 spills.

In Medway, the Motney Hill Wastewater Treatment Works in Rainham was the worst offender with 244 hours of sewage overflow alone.

The Hoo Wastewater Pumping Station also had high levels of sewage spills, totalling just under 70 hours of sewage discharge into the River Medway.

The data comes from an investigation by Unearthed, which tracked spillages from across the country and created a map showing the most affected areas.

Greenpeace UK’s journalism project showed that in 2022 there was a total of more than 300,000 hours of sewage discharged into the UK’s rivers and seas.

There were more than 16,000 spillages at Southern Water-run sites, each lasting an average of nine hours.

A spokesperson for Southern Water said: “The Environment Agency data for 2022 shows a fall in overall storm overflow activity and we are already exceeding the government’s expectations for spills per overflow. However, we know this still isn’t good enough and are working extremely hard to drive down storm overflows.

“Following the success of small-scale, innovative nature-based and engineering solutions which slow the flow of surface water into our sewer system, we are now looking to roll these out more widely over the next two years.

“Our digital monitors now cover 98.5% of our outfalls, and will hit 100% by this time next year. We will continue to report our progress in a transparent and open way.”

Cllr Simon Curry, portfolio holder for climate change and strategic regeneration said: “The water industry and its regulatory framework are broken after 13 years of Conservative government – with toxic sewage lapping up on our rivers, lakes, and seas.

“Despite this, the Conservatives have voted twice this year in Parliament to block plans by the Labour Party to end this scandal.

“Whilst other water providers felt it was appropriate to still pay out huge bonuses to their bosses, it was good to see Southern Water recognised their poor performance over the last year and opted not to. However, following a record £90m fine in 2021, there is still a long way to go.”