Southwest Environmental Limited

Thames Water Sewage Treatment Works Maps 

This map shows the location of sewage works that are owned and operated by Thames Water. The data is divided into 2 layers, that can be toggled on and off. Larger Waste Water Treatment Works (WwTW) and Smaller Waste Water Treatment Works (Small WwTW).

You can select the check boxes to choose between layers showing Small, Medium and Large Sewage Treatment Works:

• Small Size - Population served under 2000
• Full Sized - Population served greater than 2000

Note: If you click on each marker, you will be able to view asset ID, which is handy for looking things up. Like CSO performance.

Sewage Works & You 

Report a Problem

Living Next to a Sewage Works

Buying a House Near a Sewage Works

Technical Infrastructure Analysis: Thames Water Region

Thames Water Infrastructure and South East Development

Navigating the planning landscape within the Thames Water service area requires a sophisticated understanding of the UK’s most densely populated and infrastructure-heavy region. From the high-value urban infill sites of Greater London to the sensitive groundwater protection zones of the Thames Valley, our proprietary mapping of sewage treatment works (STW) provides the "True Data" necessary for site vetting. Identifying the proximity of these wastewater assets is critical for assessing development viability and ensuring that planning applications are robust enough to withstand the scrutiny of London Boroughs and regional planning officers.

Odour Impact Assessment and Cordon Sanitaire in London

In the London region, the scarcity of land often places new residential developments in extreme proximity to major wastewater infrastructure. This creates significant risks regarding odour amenity and potential "encroachment" challenges. By utilizing our proprietary Thames Water STW dataset, we perform precision Odour Impact Assessments. We integrate facility-specific source data with local meteorological patterns to verify "Cordon Sanitaire" boundaries, ensuring that new residential units are positioned safely outside of high-risk odour contours.

Nutrient Neutrality and Sensitive South East Catchments

Nutrient Neutrality has become an increasingly complex planning hurdle for developments in specific catchments served by Thames Water, particularly those affecting groundwater and the upper reaches of the Thames. Our mapping allows us to identify exactly which Thames Water asset serves a site and determine its specific capability for phosphate or nitrate stripping. This localized geospatial intelligence is essential for drafting Nutrient Neutrality Assessment and Mitigation Strategies (NNAMS) that meet the requirements of Natural England and the Environment Agency.

Strategic Drainage and London Basement Impact

The Thames Water network is under immense pressure, making Foul and Surface Water Drainage Strategies a top priority for planners. Our maps help developers visualize the relationship between their site and the wider Thames Water network, facilitating better-informed decisions regarding mains connections versus sustainable urban drainage (SuDS) requirements. By identifying nearby assets and potential capacity issues early, we help our clients avoid the "Section 106" delays often associated with wastewater discharge in the capital.

Technical Evidence for Thames Valley Planning Applications

Whether you are dealing with a complex London basement impact assessment or a large-scale residential expansion in the Thames Valley, our Thames Water dataset provides the scientific foundation for your Planning Statement. This "True Data" approach moves beyond generic desktop surveys, offering site-specific insights that are vital for discharging planning conditions. This technical capability is a key reason why SWEL has successfully delivered over 900 projects across the UK, providing a level of geospatial detail that generic reports cannot match.

Flood Risk Assessment

Lux Contour Plans