A partnership between Anglian Water and North Northamptonshire Council’s Highways team has helped protect the environment in Thorpe Malsor by reducing the risk of pollution after legacy connections were discovered within the local wastewater network.

Together, Anglian Water and North Northamptonshire Council have invested over £1 million to improve drainage capacity in the area, bringing long term benefits for customers and the environment during periods of heavy rainfall.

Following investigations into environmental spills in Thorpe Malsor, Anglian Water’s local technicians identified a number of historic highways road gullies, which collect rainwater runoff, connected into the foul sewer network in the North Northamptonshire village.

During heavy rainfall, surface water from roads and streets is meant to drain away through systems designed specifically for rainwater. But in Thorpe Malsor, extra surface water was entering pipes designed to carry wastewater, putting additional pressure on the system and increasing the risk of overflows into the environment.

Further investigations by Anglian Water’s specialist Misconnections Team and Complex Investigation and Resolution team identified 15 historic connections from highways road gullies into the foul water sewer. While these connections were originally installed appropriately, changes in the local area over time meant the additional flow from these gullies was now placing too much pressure on the local wastewater treatment processes.

Since April 2025, thee connections had contributed to more than 30 spills in the village. If left unaddressed, the extra rainfall entering the foul network could also have increased the risk of flooding for local residents and the environment.

Anglian Water worked closely with local stakeholders and North Northamptonshire Highways team to investigate the issue and develop a long-term solution. Through a collaborative effort between both organisations, the historic highway connections were removed from the foul sewer network through a scheme delivered by North Northamptonshire Council’s Highways Team

The works involved redirecting new, road gullies and the village’s trough, commonly known as a natural spring, into a new surface water drain. This solution prevents rainwater from entering the foul sewer and reduces pressure on the system during heavy rainfall.

Paul Louth, Director of Water Recycling at Anglian Water, said:

“We’ve put reducing storm overflow spills at the heart of our current business plan, with £1 billion of our largest ever, £11 billion investment programme invested into tackling the issue from every angle. There are lots of factors that can contribute to sewer spills, not all of them within Anglian Water’s control, so collaborative work like this project in Thorpe Malsor is crucial to addressing the problem.

“Working closely with North Northamptonshire Council’s Highways team to identify the issues in Thorpe Malsor has enabled us to create a solution that will reduce spills in the area for customers and the environment. The joint investment and proactive work means that spills will be reduced to fewer than 10 a year.”

Alex Hill at Kier Infrastructure said:

“This project demonstrated the value of collaboration to enable us to overcome complex site challenges. Despite working in a highly constrained environment with multiple buried services, the team remained focused on delivering the works safely and efficiently.

“I’d like to thank Anglian Water for their swift response and hands-on support on site. Their willingness to work alongside us to remove the concrete obstruction, ensured we could keep the project moving and achieve a successful outcome.”

By improving how misconnections are managed, Anglian Water is helping protect local rivers and wildlife, while also building resilience to the effects of climate change. With extreme weather events like flash downpours becoming more common, these improvements mean the local community is now better prepared.

The work forms part of Anglian Water’s largest ever business plan, worth £11 billion, which will deliver brand new infrastructure and upgrades to improve performance for customers while building greater resilience against the impacts of climate change.