A South West Water drainage misconnection programme has been recognised for its pollution-prevention work after investigations across hundreds of properties identified hidden wastewater connections entering surface-water drainage systems.
South West Water has been working with Glanville Environmental to investigate drainage misconnections across the South West during 2025 and 2026.
Misconnections can occur when household or commercial wastewater is incorrectly connected to a surface-water drain, allowing untreated wastewater to reach rivers and streams instead of being sent for treatment.
Drainage misconnection programme targets pollution at source
The joint programme uses techniques including CCTV surveying, dye tracing and geospatial analysis to establish how drainage systems are connected and identify properties requiring further investigation.
According to the UK Society for Trenchless Technology, the programme completed 359 property investigations, identifying 40 confirmed misconnections while ruling out 224 suspected cases.
The organisation also says the non-intrusive investigation approach avoided excavation and reduced the estimated carbon impact of the work by more than 70% compared with more disruptive alternatives.
South West Water explains that a foul-to-surface-water misconnection can allow wastewater from toilets, baths, sinks and appliances to discharge directly into rivers or bathing waters.
Further information on how misconnections occur and how they are investigated is available from South West Water.
Misconnection pollution work receives environmental recognition
South West Water says the joint programme has received a 2026 Green Apple Environment Award for Environmental Improvement.
The project has also been shortlisted in the Detection, Location & Inspection category of the 2026 UKSTT Awards.
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.”
Fowey Estuary investigation also shortlisted
A separate South West Water and Glanville Environmental project in the Fowey Estuary has also been shortlisted in the same UKSTT awards category.
The investigation focused on identifying tidal inflow and infiltration affecting the sewer network.
UKSTT says the project combined LiDAR modelling, tidal surveys and specialist mini-camera techniques to map approximately 1km of foreshore assets and identify active infiltration pathways.
The work was carried out using trenchless methods, avoiding excavation and creating a digital dataset that can support future intervention and asset planning.
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 expands work on misconnections
The award recognition follows wider investment by South West Water in preventing sewer misuse and drainage misconnections.
The company has previously committed £2 million to supporting households and businesses, investigating higher-risk areas and exploring new ways to identify incorrect sewer connections.
H2O Global News previously reported on South West Water’s increased investment in tackling sewer misuse and misconnections.
The winners of the UKSTT Awards are due to be announced on 30 September at Stoneleigh Park in Warwickshire.
Source: South West Water / Glanville Environmental
