Background
A planning application (MO/2023/0331) proposed three new dwellings and a car park to the rear of The Cricketers Arms public house in Ockley, Surrey.
Southern Water expressed concern that the site’s proximity to Ockley West Wastewater Treatment Works (WWTW) – approximately 220 metres – might result in odour impacts on future residents.
Mole Valley District Council, as the local authority, requested that an odour risk assessment be submitted to determine whether the development fell within any potential odour influence zone.
Anderson Acoustics was appointed by Fluid Planning Ltd to undertake the assessment and provide robust technical evidence to address the consultation response and support the planning process.
What We Did
Methodology
We applied the Anglian Water Odour Risk Assessment Framework, incorporating:
- WWTW scale (serving fewer than 1,000 population);
- Distance to nearest receptor (≈220 m);
- Presence of sludge handling (none confirmed); and
- Sensitivity of proposed residential receptors.
Using the odour footprint matrix and cross-referenced scoring system, the site scored as Low Risk, well below the 1.5 Odour Unit (OdU) contour threshold typically associated with perceptible odour
Verification and Context
GIS mapping confirmed the WWTW’s limited catchment area and screened topography between the plant and the proposed dwellings. A review of historical applications (e.g. MO/2016/0177, located closer to the same WWTW) found no record of odour complaints or mitigation requirements, supporting the low-risk classification.
Conclusion
The site lies well beyond the likely odour influence zone of Ockley West WWTW. We concluded that residential amenity would not be affected, and no additional odour mitigation was necessary.
Outcome
Southern Water’s consultation concern was resolved through quantitative evidence and the Development was cleared to proceed without any further odour assessment. Mole Valley District Council granted consent for the works on 9th August 2023.
Why It Matters
Odour assessments around wastewater infrastructure often determine whether rural developments progress or stall. By applying a transparent, defensible methodology and communicating findings clearly to both Southern Water and Mole Valley District Council, we provided planning confidence grounded in evidence.
The project demonstrates how proportionate assessment can resolve regulatory concerns early, ensuring sustainable, well-located residential growth.
