Why Look Beneath the Surface?

Drainage liabilities can result in significant and often unforeseen costs, in some cases reaching up to 10% of a property’s capital value. Understanding these risks early, particularly at the pre-acquisition and transactional due diligence stage, is critical to protecting commercial investment.

Since 1960, WJ Shirley has been the UK’s leading specialist in commercial drainage services for Transactional Due Diligence. We understand that a standard CCTV drainage survey alone does not provide a complete picture of potential financial exposure or long-term liability.

Unlike many drainage contractors, our inspections deliver a comprehensive, consultancy-led assessment of every liability associated with the drainage system. This includes;

• environmental risk
• legal and regulatory compliance
• system suitability
• structural condition,

areas frequently overlooked, yet capable of causing costly disruption, operational issues and reputational damage.

Our team of drainage specialists has expertise across all aspects of drainage consultancy and contracting, allowing us to deliver a trusted, fully turnkey service tailored to commercial property requirements.

From drainage consultancy, CCTV surveys and inspections, through to drainage repairs, groundworks and new drainage installations, our dedicated teams are committed to providing long-lasting, cost-effective solutions on every project.

In 2024 alone, approximately 30% of drainage defects identified by WJ Shirley were related to environmental risk, with associated remedial costs exceeding £8 million. This clearly demonstrates the importance of assessing all risk factors — not just structural condition.

Alongside detailed system analysis, we provide clear, practical and commercially focused advice, including realistic remedial cost forecasts, repair strategies and 5-year planned maintenance programmes.

Our asset maintenance services are regularly employed by clients to protect asset value, maintain operational performance and ensure ongoing compliance across multi-site property portfolios — a vital component of sustaining long-term commercial real estate investment.

By achieving a complete understanding of the drainage system, all risks, liabilities and associated costs are clearly identified, enabling well-informed, strategic decision-making with confidence.