Thames Water sewage discharges continue in West Berkshire, most recently in River Pang and Winterbourne Stream

Plans to upgrade a water treatment works – that has been discharging untreated sewage into a village brook – have been delayed.

A string of discharges into the Foundry Brook at Mortimer have been recorded across April, but Thames Water has now confirmed that the wait for improvements to help reduce the need to pump the sewage into the watercourse isn’t expected until next year.

The news comes as statistics show another has been discharging into the River Pang for more than 505 hours and counting since the beginning of May.

A statement on the water company’s website reads: “An upgrade is planned for Mortimer STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme is due to complete in 2023.”

But Mortimer Parish Council was told by Thames Water just last month that the wait for improvements could take far longer.

Newburytoday reported earlier this year on the scale of sewage discharge into local watercourses in West Berkshire and North Hampshire after this was revealed in a new online live overflow map.

But while Thames Water has said it is working hard to tackle the problem, sewage discharges into waterways remain an ongoing concern — with upgrades to wastewater treatment plants being delayed as late as next summer in some cases.

And recent discharges have been recorded at Mortimer, Hampstead Norreys and Winterbourne, the map shows.

A company spokesperson wrote to Mortimer councillors and said: “We provided a statement on the website recently which included a view on when we expect to be carrying out a scheme to improve performance at Mortimer STW. The forecast for us seeing the benefit from that scheme was expected by December of this year.

“We’ve had indication from the project engineer in the last few days that there is a high likelihood of the end date of this scheme being pushed back into 2024.”

It continued: “Unfortunately, there are long lead times on several items required for this project, and although we can’t be certain at this stage, the indication is that a summer 2024 completion date is more likely.

“I should point out that it is not unusual for project delivery dates do vary from month to month, as projects develop and resources and efforts are managed regularly across a portfolio of projects right across the Thames Water estate, so we can only provide a view of the likely timelines at any given time.”

More recently, discharges from Hampstead Norreys STW into the River Pang have been ongoing for more than 505 hours and counting since May 3, meaning there could be sewage in this section of the watercourse.

And the storm overflow at Winterbourne has been discharging into Winterbourne Stream for 96 hours as of Friday (May 19).

An upgrade is also planned for Hampstead Norreys STW to improve its ability to treat the volumes of incoming sewage and reduce the need for untreated discharges in that area too. The scheme is expected to be completed by 2025.

A statement on Thames Water’s website adds: “Work is also currently being carried out to reduce groundwater infiltration and other unwanted surface water entering the wastewater network in this area.

“This is due to complete by end of 2025. Further investigation will continue in this area, which will help inform our long-term planning.”

Sewage discharge is a mixture of rainwater and untreated sewage, released by storm overflows into watercourses after heavy or continued rainfall.