The hidden pollution hunt in Fowey Estuary up for an award

Some of the pollution reaching Cornwall’s rivers starts where nobody would think to look. Under a garden, behind a wall, in a pipe someone connected to the wrong drain years ago.

Work to track down exactly that kind of problem around the Fowey Estuary has now earned a place on an engineering awards shortlist, and the wider programme behind it has already picked up an international environment prize.

A pollution problem hiding underground

The culprit is something called a misconnection. It happens when wastewater from a property is connected to a surface water drain instead of the sewer network, which means that wastewater can flow into rivers and streams without ever being treated.

Misconnections are among the hardest sources of pollution to pin down. They are often buried underground and sit on customers’ own properties, so they can go unnoticed for a long time and take real effort to put right.

To tackle them, South West Water has been working with specialist environmental company Glanville Environmental to find, investigate and fix misconnections across the region.

Drones and underwater checks in Fowey

The project now shortlisted was carried out in the Fowey Estuary in 2025. The teams used inspection and surveying techniques including drone technology and specialist underwater investigations to find where groundwater and surface water were getting into the sewer network in Fowey, and where improvements could be made to protect the local environment.

It is in the running for a UK Society for Trenchless Technology (UKSTT) Award. The awards celebrate innovation and excellence in engineering and infrastructure projects.

Hundreds of properties checked

Alongside the Fowey work, teams from both companies investigated hundreds of properties across the South West through 2025 and 2026 as part of the misconnections programme, finding hidden sources of pollution and working with customers to resolve them.

That joint effort has already been recognised with a Green Apple Environment Award 2026 for Environmental Improvement, an international award for environmental best practice.

What the partners said

Dave Swiggs, South West Water’s Director of Wastewater Services, said: “We’re so proud to see the hard work we’ve done with our partners at Glanville Environmental to tackle misconnections recognised at the Green Apple Environment Awards and the UKSTT Awards.

“Protecting and improving the health of our rivers, streams and coastal waters is a key priority for South West Water, and these projects demonstrate the positive impact that targeted investment and partnership working can deliver to local communities like Fowey.”

James West, Operations Director at Glanville Environmental, said: “We are proud to have worked alongside South West Water on these award-recognised projects.

“By combining specialist investigation, surveying, and environmental expertise, we have helped identify hidden sources of pollution and deliver practical improvements that protect the region’s rivers, streams, and coastal waters. These achievements are a testament to the strong partnership between our teams and our shared commitment to environmental excellence.”

South West Water has more on what misconnections are and who is responsible for fixing them on its misconnections advice page.

The UKSTT Award winners will be announced at a ceremony at NAEC Stoneleigh Park in Warwickshire on Wednesday 30 September.

📷Teams investigating a misconnection. Credit: South West Water