25th March 2026: Updated guidance for the investigation of land potentially affected by contamination has been published, reinforcing the UK’s framework for safe, sustainable land development.
The Investigation of potentially contaminated sites – Code of practice (BS 10175:2026) is the first full revision of this key standard since 2011, providing a structured code of practice for assessing sites where harmful substances may be present due to historic industrial activities or natural processes.
The revision, published by BSI in its capacity as the UK national standards body, consolidates previous amendments and reflects evolving environmental priorities, including sustainability, climate change and worker wellbeing. In terms of sustainability, BS 10175 concentrates on practical actions that can be taken during planning and site investigations to reduce the impacts of the project on the environment and local community, achieve social goals and conserve economic resources.
Across the UK, land can contain harmful substances originating from past industrial uses, waste disposal practices or naturally elevated concentrations of certain elements. These can pose risks to human health, water resources, ecosystems and future site users. Last year, the BBC reported that thousands of sites potentially contaminated with toxic chemicals had never had checks carried out by local authorities. This new edition also now includes guidance on how to approach the possible presence of per- and polyfluoroalkyl substances (PFAS) and micro and nano-plastics, bringing newer, emerging pollutants into environmental practice.
BS 10175 provides a systematic framework for investigating such risks, ensuring robust and scientifically sound data is collected before land is redeveloped or its use changes. Its recommendations help professionals design investigations that generate reliable information on soil, groundwater, surface water and ground gas contamination.
The standard underpins the early stages of contaminated land risk management by providing guidance on setting the objectives of an investigation, developing an appropriate investigation strategy, designing phased site investigations, and undertaking sampling and field testing. It also covers laboratory analysis and the reporting and documentation required to ensure that investigations produce reliable, scientifically robust data to inform risk assessment and decision-making.
Following these principles helps ensure the data collected is appropriate for subsequent risk assessment and decision-making. It also complements related standards including BS 5930 (site investigations), BS 8576 (ground gas investigations) and the BS ISO 18400 series on soil quality.
The thoroughly revised standard reflects changing professional practice and new international standards, and introduces updates addressing:
• sustainability considerations in site investigations
• worker health and wellbeing
• expanded guidance on bioavailability and bio accessibility testing
• increased use of on-site measurement techniques
• a new informative annex covering leaching tests
Dawn Hunter, Head of Standards Development, BSI said: “Given the risks contaminated land can pose to human health, property and the environment, it’s absolutely critical that investigations of land affected by contamination are carried out consistently and to a high standard across the UK. This systematic, risk-based framework is designed to help improve the reliability of site assessments, strengthen regulatory confidence and ultimately protect both people and the environment.
“As demand grows for brownfield redevelopment and more sustainable urban growth, robust investigation of land contamination is more important than ever. The revised BS 10175 supports this by helping professionals identify and manage risks early in the development process, enabling projects to move forward safely and efficiently. With updated guidance and alignment with international standards, it continues to provide the bedrock of best practice for contaminated land investigation in the UK.”
For further information on BS 10175, visit: https://knowledge.bsigroup.com/products/investigation-of-potentially-contaminated-sites-code-of-practice-1
