Lead Local Flood Authority (LLFA): What It Is and Which Is Yours

A Lead Local Flood Authority (LLFA) is the county council or unitary authority responsible for managing local flood risk across its area: surface water, groundwater and ordinary watercourses. There are 153 of them in England. On major planning applications the LLFA is a statutory consultee on surface water drainage, so its advice on your drainage strategy has to be taken into account before permission is granted.

That last clause is where the confusion usually starts. The LLFA does not decide your application, and in practice it rarely needs to, because on a major scheme an unresolved drainage objection will stall determination whatever the planning officer thinks of everything else in the submission. Most of the delay we see at this stage is avoidable, and it is avoidable early, while the layout can still move. It is also why a surface water drainage strategy built to the authority's own standards is worth more than a generic one.

This guide sets out what an LLFA is, which council yours is, what it does, what it reads in a drainage submission, and what changed when the new National Planning Policy Framework took effect on 17 August 2026. It reflects policy as at September 2026.

Surface water is now the most widespread flood source in England, with around 4.6 million properties exposed and the figure up 43% on the previous estimate.

That figure comes from the Environment Agency's updated national flood risk assessment, and it is the pressure behind everything below: the LLFA's remit now reaches far more applications than it did a decade ago.

If you already have a site, the quickest route to the answer is a postcode. Who is my Lead Local Flood Authority, and does that same council decide my application? Both, below.

The lookup resolves the geography live from the Office for National Statistics Postcode Directory, so it follows boundary changes rather than a list that goes stale. It applies one rule: section 6(7) of the Flood and Water Management Act 2010 makes the LLFA the unitary authority for the area, or the county council where there is no unitary. Every answer carries the ONS area name and GSS code so it can be checked, and it covers England only. If you would rather read the answer off a list than type a postcode, the tables below give the same information: who is my Lead Local Flood Authority, for every authority in England.

What is a Lead Local Flood Authority?

A Lead Local Flood Authority is the council that leads on managing local flood risk under the Flood and Water Management Act 2010. In England that means a county council or a unitary authority. "Local" flood risk means flooding from surface water, groundwater and ordinary watercourses. It excludes main rivers, the sea and reservoirs, which stay with the Environment Agency.

The three sources in that definition do a lot of work on a development site, and they are not interchangeable.

• Surface water. Rainfall that runs off the ground rather than soaking in. This is the dominant source on most development sites, urban and greenfield alike, and the one the LLFA is consulted on.
• Groundwater. Water emerging from below, usually where the water table rises seasonally. It decides whether infiltration drainage is viable at all, which is why winter monitoring so often sits on the critical path.
• Ordinary watercourses. Every ditch, brook, culvert and drain not designated a main river. The LLFA consents works affecting them under the Land Drainage Act 1991, separately from planning permission.

The role came out of the 2007 floods and the Pitt Review that followed them. Before 2010 no single local body was accountable for surface water flooding, which is much of why the response to 2007 was so fragmented, and Parliament's answer was to name one authority per area and give it a defined set of statutory duties. Unda covers the origin story in the Pitt Review: impact, legacy and the gaps that remain, and the statute itself in the Flood and Water Management Act 2010 explained.

An LLFA belongs to a wider group of Risk Management Authorities that also takes in the Environment Agency, district councils, water and sewerage companies, internal drainage boards and highways authorities. Who is responsible for managing flood risk in England sets out how they fit together, the Local Government Association keeps a short summary of flood risk roles and responsibilities, and the House of Commons Library's briefing on flood risk responsibility in England is the clearest short account of how the duties divide. The government's own guidance for flood risk management authorities sets out what each one may and may not do.

What does LLFA stand for?

LLFA stands for Lead Local Flood Authority. The LLFA meaning does not shift with context: whether you meet it in an LLFA planning response, an LLFA drainage condition or an LLFA flood risk comment, it is the same council doing the same job. You will also see the plural written as LLFAs, and the term occasionally reversed to "local lead flood authority", which means the same thing but is not the statutory wording.

Two nearby abbreviations get used loosely in the same conversation, and they are not the same thing. An LPA is the local planning authority, the council that determines the application. An IDB is an internal drainage board, a separate body with drainage powers in particular low-lying areas. In a two-tier county the LLFA and the LPA are different councils, which is the single most common source of a misdirected drainage submission.

Which council is my Lead Local Flood Authority?

Your LLFA is the county council or unitary authority covering the site. In two-tier areas that is the county council. It is not the district or borough that will actually determine your application. In unitary authorities, London boroughs and metropolitan districts, one body does both jobs. There are three cases, and only three.

• Two-tier area. Your LLFA is the county council, for example Surrey County Council. A separate district or borough determines the application, with its own guidance and its own timetable.
• Unitary or metropolitan authority. Your LLFA is the unitary authority or metropolitan borough, for example Calderdale Council, and the same council determines the application. No county tier to defer to, so one authority reads everything.
• London borough. Your LLFA is the borough, and so is your planning authority — plus the London Sustainable Drainage Proforma at validation, required by all 33 London authorities since 1 April 2019.

This distinction matters more than it sounds. Two-tier means two organisations, two sets of guidance and two timetables, so that on a site in Elmbridge the borough council determines the application while Surrey County Council, as Lead Local Flood Authority, sets the drainage and SuDS requirements the application has to satisfy. Send the drainage strategy to the wrong one and it sits with a team that has no remit to comment on it. In a unitary area such as Calderdale or Kingston upon Thames the same authority reads your flood risk assessment and your drainage strategy, which is simpler, though not reliably faster.

If the site address does not make the answer obvious, find the upper-tier or unitary council for the postcode through the government's find your local council tool, then look for its SuDS or drainage planning advice pages. The table below does the same job for every authority in England.

Local standards vary far more than national policy implies: Essex restricts surface water to the greenfield 1-in-1-year rate, Somerset applies a 2 l/s/ha cap in the River Tone catchment and will not accept pumped SuDS, and none of that is in the NPPF.

Find your LLFA: all 153 Lead Local Flood Authorities in England

There is no official Lead Local Flood Authority map, no Lead Local Flood Authority finder and no published register. Neither GOV.UK, Defra, the Environment Agency nor the Local Government Association gives a count or a list, which is why "who is my LLFA?" is so much harder to answer than it should be. The postcode tool above answers it for any English site; the tables below give the same answer as a list, authority by authority. The number follows from the statutory definition, though: if the LLFA is every county council and every unitary authority, then the LLFA set is exactly the upper-tier and single-tier councils of England. Taking the government's own local government structure figures and adding them up gives the total.

153 councils in England act as a Lead Local Flood Authority, and 164 more determine planning applications without being one.

The second number is the one worth holding onto. Across most of England by area, the council you send the application to is not the council that judges the drainage.

Two-tier areas: 21 county council LLFAs

In these areas the county council is your LLFA and sets the drainage requirements. The district or borough listed alongside determines the application.

Unitary authorities and metropolitan boroughs: 98 LLFAs that are also the planning authority

In these areas one council does both jobs. The drainage requirements and the planning decision come from the same building, which removes the misdirection problem but does not remove the evidence requirements.

London: 33 LLFAs, all requiring the London Sustainable Drainage Proforma

Every London authority is its own LLFA and its own planning authority, and every one of them requires the London Sustainable Drainage Proforma at validation for major development. The proforma has been mandatory since 1 April 2019 and was developed jointly by the Greater London Authority and the London Drainage Engineers' Group. Submitting without it, or with fields incomplete, is a common cause of an application being invalidated rather than merely queried — what a SuDS proforma is and when it is required covers the form itself.

The 33 are Barking and Dagenham, Barnet, Bexley, Brent, Bromley, Camden, the City of London, Croydon, Ealing, Enfield, Greenwich, Hackney, Hammersmith and Fulham, Haringey, Harrow, Havering, Hillingdon, Hounslow, Islington, Kensington and Chelsea, Kingston upon Thames, Lambeth, Lewisham, Merton, Newham, Redbridge, Richmond upon Thames, Southwark, Sutton, Tower Hamlets, Waltham Forest, Wandsworth and Westminster.

Unda keeps a guide to the local requirements for each authority at flood risk assessments by local authority area.

What does a Lead Local Flood Authority do?

Outside the planning system, an LLFA carries six statutory duties under the Flood and Water Management Act 2010 and the Land Drainage Act 1991. Its job is to lead, coordinate and record local flood risk. It does not maintain main rivers or the coast.

Two of those produce documents worth finding before you design anything. Section 19 investigation reports, required by section 19 of the Act, are a public record of where an area has actually flooded and why, so a scheme that contradicts one will not survive consultation. The section 21 asset register will tell you whether the culvert or headwall on your boundary belongs to somebody else.

The ordinary watercourse duty is the one that catches people out. If your drainage design outfalls to a ditch you need consent from the LLFA under the Land Drainage Act 1991, separately from planning permission, and there is no retrospective route if you build first. See ordinary watercourse consent explained, and main rivers and ordinary watercourses for where the boundary between the two regimes falls.

When is the LLFA consulted on your planning application?

The LLFA has been a statutory consultee on the surface water drainage aspects of major development since 15 April 2015. "Major development" is not a matter of judgement: Article 2(1) of the Town and Country Planning (Development Management Procedure) (England) Order 2015 defines it, and any one of the following triggers it.

• 10 or more dwellings. Or a residential site of 0.5 hectares or more where the number of dwellings is not yet known.
• 1,000 square metres or more of floor space. The usual trigger for commercial, industrial and institutional schemes.
• A site area of 1 hectare or more. Whatever is being built on it, and measured as site area rather than building footprint.
• Minerals and waste development. Both are major development in their own right.

Planning Practice Guidance puts it plainly: "When considering proposals for major development the local planning authority will need to consult the lead local flood authority on surface water drainage." A site sitting entirely in Flood Zone 1, with no river or tidal risk at all, can still face a full LLFA review, because the trigger is the scale of the development rather than the flood zone it sits in. Statutory consultees in planning explained sets out how the LLFA's 21-day response window works alongside the Environment Agency's and everyone else's.

Below the threshold there is no statutory duty to consult, and this is where the position changed materially in August 2026. Policy F8 of the new Framework applies its SuDS design and maintenance requirements to all development, major or minor, while leaving the duty to take LLFA advice attached to major applications only. So a minor scheme now carries the drainage standards without automatically carrying the consultee. Plenty of authorities consult anyway: some designate critical drainage areas where smaller schemes are caught, and Mid Sussex runs its own in-house flood risk and drainage team that reviews minor applications too.

No consultee does not mean no requirement — since 17 August 2026 the SuDS standards bite on every development with drainage implications, whether or not the LLFA is formally consulted.

What does the LLFA actually read in your drainage strategy?

The LLFA is checking one thing: whether the development can manage its own runoff without increasing flood risk elsewhere. It is not assessing the scheme's planning merits, its architecture, or its flood risk from rivers, and it will work through the surface water case in a fairly consistent order regardless of how the report itself is arranged.

1. Where the water goes. Whether you have worked down the discharge hierarchy, from reuse to infiltration to a watercourse to a surface water sewer and only then to a combined sewer, and evidenced why you stopped where you did. Cost alone has never been sufficient justification for dropping a tier. The SuDS hierarchy explained works through each step.
2. Whether you tested that assumption. Infiltration has to be demonstrated by in-situ testing to BRE Digest 365, not assumed from a geology map. This is the single most common failure point, and the cheapest to avoid. When infiltration testing is required sets out the three-part test.
3. The discharge rate and the calculations behind it. Restricted to the greenfield runoff rate the authority specifies, modelled to the 1 in 100 year event with a current climate change allowance and an urban creep uplift.
4. What happens when the design event is exceeded. Exceedance flow routing: where water goes in a storm bigger than the one you designed for, or when something blocks. Consistently requested, consistently missing.
5. Who maintains it, and for how long. A whole-life maintenance plan for every drainage feature, with the responsible party named. Policy F8 now requires this on minor schemes too.

Unda's surface water drainage strategy service covers all five, and what drainage information is needed for planning permission sets out what belongs in the application against what can reasonably be left to a condition. If you are proposing infiltration, check the ground before you commit the layout to it: Unda's soakaway ground conditions checker and BRE 365 infiltration rate calculator are both free.

Two things changed the standard in 2025 and 2026

What the LLFA measures you against has moved twice in eighteen months. Defra published updated National Standards for Sustainable Drainage Systems on 19 June 2025, the first refresh in a decade, setting seven standards covering runoff destinations, interception, extreme rainfall, water quality, amenity, biodiversity and maintenance. They were guidance with no legal force. Policy F8 then gave them planning weight, and Unda works through them in the 2025 National Standards for SuDS.

Then the paperwork changed too. The Chief Planner's newsletter of 18 August 2026, a day after the Framework took effect, announced two national SuDS Strategy Templates. They were produced by the Environment Agency with CIRIA, the Association of SuDS Authorities and Arup: a full one for major development, a proportionate one for everything else. The Environment Agency is encouraging every planning authority and LLFA to adopt them in place of local forms, so a strategy prepared to the template should travel across authority boundaries without being reformatted. That does not make the local variation above disappear. It is, though, the first serious attempt to standardise the form it arrives in.

Does the LLFA's advice bind the planning authority?

No. The LLFA advises and the local planning authority decides. Its response is a material consideration the planning authority must take into account, but the LPA can grant permission against it, and occasionally does, usually where the objection is technical rather than fundamental and can be dealt with by a well-drafted condition instead.

That distinction is narrower than it looks, because national policy points the same way. The relevant policy is no longer the paragraph most reports still cite. The National Planning Policy Framework published on 17 August 2026 replaced the December 2024 Framework in full and moved flood risk into a dedicated Chapter 18 with nine coded policies, F1 to F9. Sustainable drainage is now Policy F8, and old paragraph 182 no longer exists as national policy.

Under Policy F8 major development must still take account of advice from the Lead Local Flood Authority, so the LLFA's standing on a major scheme is unchanged. What changed is the standard it applies, which is now national rather than local, and the reach of that standard, which now extends to minor development. The August 2026 NPPF changes for flood risk and drainage maps every old paragraph to its new policy code, and a report drafted now should cite the F codes rather than the December 2024 numbering.

An officer granting permission over a live drainage objection has to explain in writing why the advice was outweighed, and few will attempt that on a major application when the alternative is simply waiting for better evidence. That is why an unresolved LLFA objection works as a stop even though it is formally only advice.

There are limits on what an LLFA can ask for, and they are worth knowing. It cannot use a condition to make you fix flooding you did not cause, which betterment planning conditions covers. For the decision-maker's side of the same relationship, see what is a local planning authority.

What happens if the LLFA objects?

Most LLFA objections are holding objections, which pause determination until the drainage evidence is resolved rather than rejecting the development in principle. The usual cause is a strategy that went straight to sewer discharge without testing infiltration first, and the usual fix is more evidence rather than a redesign.

This is where applications most often stall, so Unda covers it separately and in depth. LLFA objection: how to fix your drainage strategy works through each common objection, the evidence that clears it, and when a revision will do instead of starting again. One timing point is worth flagging here: the April 2026 appeal reforms largely bar new technical evidence at appeal, so resolving an objection during the application is now materially safer than contesting a refusal afterwards.

LLFA, LPA or the Environment Agency: who reviews what?

Three bodies can look at flood risk on the same application, and the line between them runs by flood source rather than by document.

• The Environment Agency. Flood risk from main rivers, the sea and reservoirs. Consulted on development in Flood Zones 2 and 3 and within 20 metres of a main river. See the Environment Agency: flood risk and planning.
• The Lead Local Flood Authority. Surface water, groundwater and ordinary watercourses. Consulted on the drainage strategy for major development.
• The local planning authority. The decision-maker. Weighs both responses and determines the application.
• Internal drainage boards, where they exist. A separate body with its own consenting powers in particular low-lying districts, sitting alongside rather than instead of the LLFA. See why internal drainage boards matter for planning.

On a riverside major scheme you will deal with the first three, and it is worth being clear that the Environment Agency is not consulted on surface water at all. If you are unsure which reports your site needs, flood risk assessment and drainage strategy: do you need both? works through the decision.

When your LLFA changes: reorganisation in 2027 and 2028

Every one of the 21 county council LLFAs is due to be replaced by new unitary authorities. The dates are not what most guidance still says. Surrey goes first, on 1 April 2027. Everywhere with a decision, the vesting day is 1 April 2028. Until vesting day the existing county council remains the LLFA for every live application, so nothing changes for a scheme in the system now.

The government's written ministerial statement of 16 July 2026 confirmed the July decisions, and Surrey's two-unitary model was confirmed in October 2025. Authority names for 2028 are working titles until the Structural Change Orders are made, and the Local Government Association tracks each area's status. Local government reorganisation and what it means for flood risk and planning covers the transition in full.

A scheme being designed now in a two-tier county will very likely be built under a different Lead Local Flood Authority than the one that reviews its drainage strategy.

The practical implication is about evidence rather than dates. Local standards, adopted proformas and drainage design guides all belong to authorities that are about to be dissolved, and a new unitary will take time to publish its own. Anything agreed in writing with the current LLFA — a discharge rate, an accepted infiltration result, a pre-application position — is worth having on file before the reorganisation, because institutional memory is what gets lost on vesting day.

Getting the drainage right before it reaches the LLFA

LLFA requirements are cheapest to meet while the layout can still move. Infiltration testing, groundwater monitoring and a discharge point that actually works are constraints on the site plan, not additions to it. Treat them as a reporting exercise to be picked up once the masterplan is fixed and a straightforward scheme turns into an expensive one. Retrofitting attenuation is where budgets and programmes go. By then the cheap options have gone.

Since 17 August 2026 that has become more pressing rather than less, because Annex C of the Framework requires a SuDS statement demonstrating compliance with the national standards for any proposal that could affect drainage. Drainage design has moved to the front of the programme, not the conditions stage.

Unda prepares surface water drainage strategies and SuDS designs, flood risk assessments for planning and drainage strategies for planning applications, written to the specific authority's standards rather than a generic template. If a scheme will need LLFA sign-off, our chartered flood risk and drainage team will give you a free, no-obligation quote. Where a condition is already attached, we handle the discharge of drainage conditions too.

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