The Section 19 Reference Manual

The legal foundation

1.1 What Section 19 says

Section 19 of the Flood and Water Management Act 2010 establishes a statutory duty on Lead Local Flood Authorities. The text of the relevant subsections:

(1) On becoming aware of a flood in its area, a lead local flood authority must, to the extent that it considers it necessary or appropriate, investigate —
(a) which risk management authorities have relevant flood risk management functions, and
(b) whether each of those risk management authorities has exercised, or is proposing to exercise, those functions in response to the flood.

(2) Where an authority carries out an investigation under subsection (1) it must —
(a) publish the results of its investigation, and
(b) notify any relevant risk management authorities.

Three things to notice in this text.

First, the duty is mandatory in principle. The LLFA "must" investigate — but only "to the extent that it considers it necessary or appropriate." This is a qualified duty. The LLFA has discretion about whether any given flood event meets the threshold. That discretion is the most common point at which homeowners are turned away.

Second, the focus of the investigation is structural, not personal. Section 19 does not require the LLFA to investigate the impact on individual properties. It requires the LLFA to identify which Risk Management Authorities had relevant functions and what they did. The investigation answers institutional questions, not personal ones.

Third, the LLFA must publish the result. This is the critical practical lever. Once a Section 19 investigation is conducted, the report becomes a public document, available to homeowners, insurers, future legal proceedings, journalists, and other authorities. The published report is what creates the evidence base for everything that follows.

1.2 Who counts as a Risk Management Authority

The Act identifies seven categories of body as Risk Management Authorities (RMAs):

1. The Environment Agency
2. Lead Local Flood Authorities (the upper-tier or unitary council)
3. District councils (for ordinary watercourses in two-tier areas)
4. Internal Drainage Boards
5. Highways authorities
6. Coastal Protection Authorities
7. Water and sewerage companies (for foul and surface water systems)

In a typical flood event, several of these will have relevant functions. Surface water flooding may involve the highway authority (road drainage), the water company (storm drains), and the LLFA (ordinary watercourses and surface water management). River flooding involves the Environment Agency. The investigation must determine which authorities had functions and what each did.

This matters because when something has gone wrong, it is rarely the case that no authority had any responsibility. The Section 19 process is designed to surface where responsibility actually sat.

1.3 What the LLFA is

A Lead Local Flood Authority is the upper-tier or unitary council responsible for managing flood risk from surface water, groundwater, and ordinary watercourses (watercourses other than main rivers). In two-tier areas, the LLFA is the county council. In unitary areas, the LLFA is the unitary authority.

For the four counties RISE serves:

• Buckinghamshire — the LLFA is Buckinghamshire Council (unitary)
• Oxfordshire — the LLFA is Oxfordshire County Council
• Northamptonshire — the LLFAs are North Northamptonshire Council and West Northamptonshire Council (which became unitary in April 2021)
• Bedfordshire — the LLFAs are Central Bedfordshire Council, Bedford Borough Council, and Luton Borough Council (each unitary for their own area)

If your home is in one of these counties, the relevant LLFA is one of the above, depending on your specific location.

When the LLFA must investigate

2.1 The statutory test

The Act requires investigation "to the extent that the LLFA considers it necessary or appropriate." There is no single national threshold. Each LLFA publishes its own criteria within its Local Flood Risk Management Strategy. These criteria vary, but follow common patterns.

2.2 The typical trigger framework

Most LLFAs operate around three categories of trigger:

Property thresholds — based on the number of residential properties internally flooded in a single event, with a higher threshold for events spanning a wider catchment, and a separate trigger for repeat internal flooding at a single property within a defined window.

Infrastructure thresholds — based on the flooding of critical national infrastructure such as schools, hospitals, electricity substations, transport hubs, or sustained closures of major transport routes.

Severity thresholds — based on threat to life, serious injury, or flooding affecting properties not previously identified as at risk.

The specific numbers vary council by council. Some LLFAs publish their thresholds prominently in their flood risk management strategy; others bury them or apply them with material discretion. The specific threshold relevant to your case depends on which LLFA covers your property and how that LLFA interprets its own criteria.

2.3 Why the threshold question is harder than it looks

The framework above sounds clear. In practice, the threshold question is the single most common point at which Section 19 cases stall, for three reasons.

The first is that the criteria are qualitative as well as quantitative. "Critical national infrastructure" is not exhaustively defined. "Sustained closure" is not specified in hours. "Properties not previously identified as at risk" requires reference to flood maps that may themselves be incomplete.

The second is that thresholds are applied by people. A council facing capacity constraints, political sensitivities, or institutional defensiveness may apply its own criteria narrowly. A council with a more proactive flood team may apply the same criteria generously. The same flood event can meet the threshold in one council and not in the neighbouring one.

The third is that the statutory test ("necessary or appropriate") gives the LLFA additional discretion beyond their published criteria. A case that strictly meets the threshold can still be declined if the LLFA judges investigation unnecessary; a case that strictly fails the threshold can still be investigated if the LLFA judges it appropriate.

The practical consequence: the threshold question for any specific case requires judgement on which criterion applies most strongly, how the relevant LLFA is likely to interpret it, and how to evidence the case persuasively. That judgement is the work of a case assessment, not of a reference manual.

2.4 The single most important fact about the trigger

The LLFA is required to investigate "on becoming aware" of a qualifying flood. They cannot become aware of something they have not been told about.

This means: a flood that nobody reports formally to the council may not trigger the Section 19 process even where the criteria are clearly met. Reporting the flood through the council's formal channels is itself a precondition for the duty to engage.

Many flooded homeowners spend the early days dealing with the immediate impact and never formally report the flood to their council. The insurer is told; the council is sometimes not. This is one of the major reasons Section 19 is under-used.

What an investigation does, and does not, do

This is the most misunderstood part of the Section 19 process.

3.1 What an investigation will do

A Section 19 investigation will:

• Establish a factual timeline of what happened
• Identify which RMAs had relevant functions
• Determine what each RMA did or did not do in response
• Identify the most likely physical cause of the flooding (in general terms)
• Make recommendations to the relevant RMAs
• Publish the findings as a public document

3.2 What an investigation will not do

A Section 19 investigation will not:

• Provide hydraulic modelling of the flood mechanism in technical detail
• Recommend specific engineering solutions
• Award compensation
• Hold any individual or organisation legally liable
• Force any RMA to take specific subsequent action
• Address individual property-level damage or recovery

The investigation is structural, not personal. It tells you who was responsible and what they did. It does not tell you what to do next, and it does not force the RMAs to act on its findings.

3.3 Why an investigation is still worth pursuing

The investigation's value is the published evidence base it creates. Once a Section 19 report exists, it is a public document that establishes the official council position on what caused the flood. It identifies which RMAs are responsible for further action. It can be used as evidence in insurance claims, regulatory complaints, and litigation. It creates political pressure for the identified RMAs to act on the recommendations. It informs future flood risk management planning and capital scheme prioritisation.

In the case that informs this manual, the published Section 19 report did not force the council to undertake any specific work. But the public record it created, combined with sustained engagement by the affected homeowners and the local councillor, contributed to the subsequent commitment of over £2 million in council-funded infrastructure works to address the cause. The report was the foundation. The sustained engagement was the lever. Both were necessary.

3.4 The July 2025 government guidance

In July 2025, the UK government published Investigating a flood: guidance for lead local flood authorities, providing a supporting framework for LLFAs conducting Section 19 investigations. The guidance is not statutory, but it sets out good practice and is increasingly cited by councils as the standard against which their investigations are conducted.

The 2025 guidance emphasises consistency across LLFAs, engagement with affected communities, collaboration between RMAs, and recommendations aimed at positive outcomes. For homeowners, the existence of this national guidance is useful leverage. If a council's investigation falls visibly short of the published government framework, that gap can be raised in correspondence and complaint.

The four steps to trigger an investigation

A Section 19 case engages through four sequential steps. Each step is conceptually simple. The success of each step depends on how it is executed — what is in the request, who is copied, what evidence supports it, how the council is held to its timeline.

4.1 Report the flood formally

The LLFA must be "aware" of the flood through their formal reporting channels. Emergency calls, casual contact, and word-of-mouth do not usually count. The formal channel is typically a flood reporting form on the council's website or an email to a flood@ or floodrisk@ address.

4.2 Request a Section 19 investigation explicitly

Reporting the flood is not the same as requesting an investigation. A formal report tells the council something happened. An explicit Section 19 request invokes the statutory duty, sets the legal basis, and creates a written record the council must respond to.

4.3 Document the wider event

If the flood affected more than just your property, the wider picture significantly strengthens the case. Aggregating affected neighbours, documenting infrastructure impact, and providing the council with a complete picture of the event is what often converts a marginal case into a strong one.

4.4 Track the timeline

Section 19 investigations typically take 9 to 12 months from initiation to publication. Some take longer. Material exceedance of expected timelines, without explanation from the council, is itself grounds for further engagement.

When a council fails to engage properly

Sometimes the council declines to investigate. Sometimes they investigate but the report is thin or omits material RMA responsibilities. Sometimes they commit to investigate and then nothing happens. In each case, five escalation routes exist, in approximate order of escalation.

5.1 Challenge the decision in writing

The first response to any council decision — a decline, an inadequate report, a stalled investigation — is a written challenge that addresses the council's specific reasoning. The challenge is most effective where it cites the council's own published criteria, the 2025 government guidance, and any evidence the council overlooked.

5.2 Councillor engagement

A councillor asking the council to revisit a decision is harder to brush off than a homeowner asking the same question. Councillor engagement is the most reliable non-statutory lever in a Section 19 case.

5.3 MP engagement

For cases where councillor engagement has not produced movement, the MP is the next tier. MPs rarely overturn council decisions directly, but their involvement substantially raises the visibility of a case.

5.4 Formal complaint to the council

A formal complaint creates a parallel paper trail and triggers the council's internal complaints process. The complaint is also the precondition for escalation to the Local Government and Social Care Ombudsman (LGSCO).

5.5 LGSCO escalation

If the council's complaints process concludes without resolution, the LGSCO can investigate maladministration in the council's handling of the Section 19 process. The LGSCO cannot compel an investigation but can require the council to revisit its decision-making.

Using a published report as evidence

Once a Section 19 report is published, it becomes a usable instrument across six contexts. The framework for each is summarised here. The tactical execution — how to deploy the report effectively in any specific context — depends on the specifics of the case and the report's content.

6.1 Insurance claim disputes

If an insurer disputes the cause of damage or scope of cover, the Section 19 report establishes the official council finding on cause. Where the report identifies a specific mechanism, the insurer cannot easily argue against it without contradicting the council's published position.

6.2 Financial Ombudsman Service complaints

The Section 19 report is admissible evidence in an FOS complaint against an insurer. FOS treats council-published reports as authoritative on matters of fact.

6.3 Pursuing responsible RMAs

The report identifies which RMAs had relevant functions and what they did or failed to do. Where the report identifies a failure to exercise statutory functions adequately, that finding is the basis for further engagement with the identified RMA. This is the lever that, in the case underlying this manual, led to substantial subsequent infrastructure works.

6.4 LGSCO and regulatory complaints

If an identified RMA fails to act on the recommendations, the Section 19 report becomes the basis for a complaint to the relevant regulator: the LGSCO for council RMAs, Ofwat for water companies, the Environment Agency for EA failures.

6.5 Future legal proceedings

The published report is admissible evidence in civil proceedings. If a property floods again in similar circumstances, the published report from the first event becomes evidence of foreseeability and prior notice — relevant to any subsequent civil claim against responsible parties.

6.6 Property transactions

A published Section 19 report may be picked up in property searches by future purchasers. This formally records the property's flood history and the council's response to it — a double-edged factor that documents both the issue and what has been done about it.

Alternative routes where Section 19 is not the right tool

Section 19 is the most powerful tool for flood investigation, but it is not the only route to homeowner-side action. Where Section 19 does not apply or has not delivered an adequate outcome, alternative routes include:

Highway drainage complaints. If road drainage contributed to flooding, the highway authority has duties under the Highways Act 1980 that can be the basis for complaint and, in some cases, claims for compensation.

Water company complaints. If sewer backup or storm drain failure contributed, the water company is the responsible body. Water companies are regulated by Ofwat and the Environment Agency. Initial complaint is to the water company directly; escalation is via the Consumer Council for Water and potentially Ofwat.

Environment Agency engagement. For main river flooding, the EA is the responsible RMA. Their local teams (split by river catchment) are the appropriate first contact.

Riparian owner action. Where the source of flooding is an ordinary watercourse not maintained by the LLFA, the immediate riparian owners have legal responsibilities under common law. The LLFA can issue notices requiring riparian owners to maintain their watercourses; failing that, civil remedies may apply.

Civil litigation. As a last resort, civil action against a specific RMA or contractor whose negligence is documented can be appropriate. This is expensive and slow, and should normally be a last resort after Section 19 and alternative regulatory routes have been exhausted.

Glossary of key terms

LLFA — Lead Local Flood Authority. The upper-tier or unitary council responsible for managing flood risk from surface water, groundwater, and ordinary watercourses.

RMA — Risk Management Authority. Any of the seven categories of body with statutory flood risk management functions.

FWMA 2010 — The Flood and Water Management Act 2010. The primary legislation establishing the Section 19 duty.

Ordinary watercourse — A watercourse that is not a designated main river. The LLFA has responsibility for ordinary watercourses; the Environment Agency has responsibility for main rivers.

Riparian owner — A landowner whose property adjoins a watercourse. Riparian owners have common law responsibilities to maintain their stretch of the watercourse.

Local Flood Risk Management Strategy — Each LLFA's published strategy document setting out their approach to flood risk management, including their criteria for Section 19 investigations.

Section 19 report — The published report produced at the conclusion of an investigation under Section 19 of the FWMA 2010.

LGSCO — Local Government and Social Care Ombudsman. The independent body that investigates complaints about council maladministration.

FOS — Financial Ombudsman Service. The independent body that investigates complaints against financial services firms, including insurers.

The honest summary

Section 19 cases succeed or fail on five factors. None of them are written in the statute. All of them require judgement applied to the specific facts of a specific case.

The framework in this manual prepares you to recognise these factors. Acting on them in your specific case is what RISE does.

Where this manual ends and case work begins

This manual is intentionally a framework, not an instruction guide. The framework is genuinely useful — for understanding what Section 19 is, when it applies, what it can and cannot achieve, and what factors determine outcomes. It is what every flooded homeowner in England should read before deciding what to do next.

It is not, on its own, enough to win a Section 19 case. A real case requires judgement on your specific situation: which threshold criterion applies to your event, how your LLFA is likely to respond, what evidence you have and what gaps exist, how to phrase the request so it cannot be easily declined, who to copy and when, and how to escalate if the initial response is inadequate.

That judgement is what RISE provides through the Section 19 Case Assessment. It is the natural next step for a homeowner who has read this manual and wants a specific, written, personalised evaluation of their case before acting.