After a flood event, the Lead Local Flood Authority (LLFA) creates section 19 reports on exactly what happened. Our team, however, can carry out a section 19 flood investigation to address the issue and likely causes.
Last updated: March 2026
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A Section 19 flood investigation is a formal report triggered after a significant flood event.
Under the Flood and Water Management Act 2010, the Lead Local Flood Authority (LLFA) must investigate which risk management authorities have relevant functions and whether they have exercised them.
It isn’t about assigning blame; it’s about understanding exactly what happened so we can better manage future risks.
The Trigger: Investigations usually happen when flooding hits a specific threshold, such as affecting a certain number of properties or critical infrastructure.
The Goal: The report identifies the causes of the flood and recommends actions for authorities like the Environment Agency or local councils.
Your Role: If your development site is affected by a Section 19 investigation, you’ll need to work closely with the LLFA to ensure your drainage strategy and flood risk assessments align with their findings.
We help you navigate these complex reports, liaising with stakeholders and local authorities to keep your project moving forward. Whether you’re dealing with surface water issues or working near ordinary watercourses, we provide the expert advice you need to stay compliant.
Need help with a flood investigation or watercourse consent? Get in touch for a quick quote.
For both developers and local communities, surface water and fluvial flooding are a concern. Flood risk threatens businesses, commercial viability, critical infrastructure and residential properties, especially in areas under pressure from urban expansion and extreme weather events.
In England and Wales, the Lead Local Flood Authority (LLFA) plays an essential role in flood response, providing section 19 reports whenever a reported flooding incident causes damage or disruption and meets certain criteria outlined in legislation, such as internal property flooding or damage to assets managed by highways authorities.
While the Flood and Water Management Act 2010 insists that LLFAs investigate significant flood incidents, they often rely on consultants to perform the technical investigation and provide supporting analysis.
Our team of flood risk consultants provides independent and site-specific support to developers, insurers and local authorities, offering insight into relevant flood risk management, identifying infrastructure failures, presenting evidence for planning and legal processes, and influencing outcomes during appeals or mitigation planning.
A section 19 flood investigation provides an opportunity for a flood risk consultant to collect data, liaise with relevant risk management authorities (RMAs), and carry out in-depth analysis with hydraulic modelling to better understand flood dynamics. The outcomes then contribute to the production of section 19 reports, supporting planning, insurance matters and long-term mitigation strategies.
The Flood and Water Management Act requires LLFAs to investigate flood incidents that significantly affect people, property or infrastructure. The LLFA will investigate incidents to identify the causes of flood events, assess the performance of risk management functions, and confirm the roles of organisations such as the Environment Agency (EA) and other RMAs.
Although the LLFA is responsible for overseeing the investigation, a consultant from our team can lead the technical aspects, conduct a parallel assessment, and support compliance with planning conditions, development requirements and broader regulatory obligations.
A section 19 investigation conducted by our team will be needed whenever the following criteria are met, such as:
Even a cluster of internally flooded homes within a small catchment area may qualify as a significant flood incident in the eyes of LLFAs, leading to the need for an S19 investigation.
Over the course of an S19 investigation, it is important that the process seeks to establish responsible parties, such as the EA, relevant flood risk management authorities, water companies and the Met Office.
By working in collaboration with them, the developer will hold accountability, enhance planning outcomes, and positively influence mitigation efforts or funding priorities.
Our S19 investigative process includes:
After the investigation, we produce reports that help to meet the requirements set out in legislation.
Section 19 reports detail the sequence of events, the actions of relevant risk management authorities, and the recommended reduction or alleviation options to prevent the same actions from happening again in the future.
With our input on an S19 report, you can receive support with future planning applications, infrastructure upgrades and public consultations.
As well as meeting the conditions of relevant bodies, flood investigations additionally support legal and policy-based decision-making around drainage and flood response.
Instead of just allocating legal liability, section 19 reports provide in-depth analysis that developers, insurers and asset owners can use when proposing to exercise development rights or appeal planning decisions.
Stepping in to help developers with interpreting section 19 reports, our team has prepared supplementary analysis and impartial investigations for areas with a previous flood event or a history of flooding issues.
For a free quote based on your development site and plans, reach out to our team over email, phone or by completing a quote form online. We will then speak to you about the likely cost of an inspection and tell you everything you need to know about how our services work.
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