Flood Risk & Drainage Requirements for East Lindsey District Council

Getting a development through East Lindsey is rarely a conversation with one authority. A site on the Lincolnshire coast or in the fens behind it can answer to four separate bodies on water alone: East Lindsey District Council decides the planning application, Lincolnshire County Council checks the surface-water drainage as Lead Local Flood Authority, the Environment Agency leads on the tidal coast and the main rivers, and an Internal Drainage Board holds its own consent over anything discharged into its watercourses. Knowing which one wants what, and when, is the difference between a clean submission and one that stalls for months.

We prepare flood risk assessments and drainage strategies for developments across East Lindsey's area for planning, property purchase, mortgage and insurance, and BREEAM, alongside sequential and exception tests and surface-water drainage strategies (SuDS). This page sets out what East Lindsey District Council requires for flood risk and drainage on a planning application: the Local Plan policies and their codes, the documents the validation list asks for, the county's role as Lead Local Flood Authority, and the Internal Drainage Board consent that catches applicants who have only planned for the council and the Environment Agency.

If you want to talk an East Lindsey site through or need a quote, contact one of our experienced flood risk consultants on 01293 214444 or email enquiries@unda.co.uk.

In East Lindsey the drainage case is often harder than the flood-risk case. A coastal or fen site can need written discharge consent from an Internal Drainage Board under its own byelaws before the council will accept the scheme — a step that sits entirely outside the Environment Agency and one that a national flood map never shows.

Flood risk and drainage in East Lindsey at a glance

• East Lindsey District Council is the planning authority. It determines your application against its adopted Local Plan Core Strategy (adopted July 2018) and its validation list. Lincolnshire County Council is the Lead Local Flood Authority for surface water.
• Coastal flooding can affect around 38% of the district. The Environment Agency's Coastal Flood Hazard Map defines a Coastal Zone where the council's policies SP17 and SP18 tightly control what can be built.
• Two flood-and-drainage policies lead the plan. Policy SP16 (Inland Flood Risk) and Policy SP17 (Coastal East Lindsey) set the local tests, backed by Policy SP18 on coastal housing and the district's Strategic Flood Risk Assessment.
• Internal Drainage Boards cover much of the district. Lindsey Marsh Drainage Board — the largest IDB in England — and the North East Lindsey board manage the low-lying marsh and fen, and their consent to discharge surface water is a genuine requirement here.
• The 2019 Wainfleet flood is the local reference point. A breach of the River Steeping relief channel flooded homes and evacuated around 1,000 people, and it still shapes how strictly flood risk is scrutinised across the district.

Who decides flood risk and drainage in East Lindsey?

Four bodies share the job. East Lindsey District Council is the local planning authority that determines the application. Lincolnshire County Council is the Lead Local Flood Authority (LLFA) and statutory consultee on surface-water drainage for major development. The Environment Agency leads on the main rivers and the tidal coast. And across much of the low-lying district an Internal Drainage Board runs its own consenting regime. Most stalled applications here come from answering one of these and forgetting another.

East Lindsey is a two-tier district, so planning and drainage are not decided by the same organisation. The district council registers and determines your application and applies its Local Plan flood and drainage policies. Lincolnshire County Council, sitting above it as the county authority, is the LLFA: on major development it is a statutory consultee and its view on your surface-water strategy carries real weight. The role the LLFA plays and the way a local planning authority handles flood and SuDS are worth understanding before you submit, because the two work to different remits.

• East Lindsey District Council (LPA). Determines the application, applies Policies SP16, SP17 and SP18, and runs the validation list. Based at The Hub, Mareham Road, Horncastle.
• Lincolnshire County Council (LLFA). Statutory consultee on surface-water drainage for major development; sets the SuDS and discharge expectations your drainage strategy must meet.
• Environment Agency. Leads on the tidal coast, the Coastal Flood Hazard Map and the main rivers such as the Steeping, Lymn and Witham. An EA objection on a coastal site is difficult to overturn late.
• Internal Drainage Boards. Lindsey Marsh Drainage Board and the North East Lindsey board manage water levels across the marsh and fen and must consent to surface-water discharge into their watercourses.
• Anglian Water. The sewerage undertaker, consulted where a scheme proposes to connect to the public sewer as a last resort in the drainage hierarchy.

Does an East Lindsey application need a flood risk assessment or a drainage strategy?

Most non-trivial development in East Lindsey needs a flood risk assessment, a surface-water drainage strategy, or both. National triggers apply — any site in Flood Zone 2 or 3, any site of one hectare or more, and major development — but the district's geography adds local triggers that catch sites a national map alone would wave through: the coastal flood zone, the surface-water and groundwater risk across the low-lying land, and the Internal Drainage Board areas.

Because so much of East Lindsey sits low and flat, surface water and groundwater matter as much as the rivers and the sea. Since the September 2025 PPG update, surface-water risk on the Flood Map for Planning can trigger an assessment even on a Flood Zone 1 site, and groundwater rising through the fen and marsh deposits will not appear on a river map at all. The table below is a guide, not a substitute for checking the specific site.

If you are not sure which of these your site falls into, send us the address. You can also screen a postcode on our free flood risk map before you commit to anything. Getting the scope right early is what keeps an application out of the invalidation pile.

East Lindsey's Local Plan flood and drainage policies

East Lindsey judges flood risk and drainage against its adopted Local Plan Core Strategy, adopted in July 2018. Three strategic policies do most of the work: Policy SP16 on inland flood risk, Policy SP17 on the coast, and Policy SP18 on coastal housing. A robust application quotes the right policy and shows, point by point, how the scheme meets it. The full policy wording sits in the council's adopted Local Plan Core Strategy.

Policy SP16 — inland flood risk

Policy SP16 in the East Lindsey Core Strategy requires development to take an integrated approach to sustainable drainage that produces positive gains for the natural environment, and it expects development in areas of inland flood risk to be properly justified and to build flood mitigation into its design. In practice that means the drainage strategy and the flood risk assessment are read together: the council wants to see that surface water has been designed for from the outset and that the scheme does not increase flood risk elsewhere in a district where water has nowhere easy to go.

Policy SP17 — coastal East Lindsey

Policy SP17 requires all relevant development within the Coastal Zone to provide adequate flood mitigation, and it supports investment in flood defences and the infrastructure that emergency planning depends on. Because the Environment Agency's Coastal Flood Hazard Map covers a large part of the district, a coastal application has to address tidal flood risk and the residual risk that remains behind the sea defences over the development's lifetime, allowing for climate change and sea-level rise.

Policy SP18 — coastal housing

Policy SP18 restricts new housing in the coastal flood-risk zone to existing commitments, with limited exceptions for affordable housing, conversions and the reuse of brownfield land. It is the first policy to check on a coastal housing scheme, because a proposal that does not fall within one of its categories can fail on principle regardless of how strong the flood case is. The wider plan also notes that East Lindsey lies in an area of serious water stress, which shapes how water is treated across the district.

East Lindsey's Strategic Flood Risk Assessment

East Lindsey's Strategic Flood Risk Assessment (SFRA) is the evidence base the council uses to apply the sequential, risk-based approach and to test where development can go. The current adopted SFRA dates from 2017, and an updated Level 1 and Level 2 SFRA is being prepared to support the district's emerging new Local Plan, with the Level 2 work focused on a strategy for safe development within the coastal flood zone. The council publishes the current version and updates on its Strategic Flood Risk Assessment page.

An SFRA is a strategic, district-wide document rather than a site report, but it matters to an individual application in two ways: it sets the flood-zone and climate-change picture the council starts from, and it underpins the sequential and exception tests that decide whether higher-risk land can be developed at all. A site-specific flood risk assessment for planning then works within that framework, using finer local data to show the actual site can be made safe. Because a revised SFRA and a new Local Plan are on the way, the policy position here is one to keep checking — our note on climate-change allowances explains why an assessment must look decades ahead.

East Lindsey's drainage and SuDS requirements

Drainage is often the harder half of an East Lindsey application. Lincolnshire County Council, as Lead Local Flood Authority, expects surface water to be managed down the SuDS hierarchy and discharged at a controlled rate agreed in writing, and where a site drains into an Internal Drainage Board's watercourse the board's own written land drainage consent is needed as well. On low-lying, poorly-draining ground the receiving watercourse often has little spare capacity, so the discharge rate is the number the whole scheme turns on.

The starting point is the SuDS hierarchy set out in the 2025 national standards for sustainable drainage: reuse first, then infiltration, then a watercourse, then a surface-water sewer, and only as a last resort a combined sewer. Infiltration is the catch in East Lindsey — across much of the marsh and fen a high water table and low-permeability ground mean soakaways do not work, so most schemes fall to a controlled discharge into a watercourse. That is where the LLFA's discharge rate and the IDB's consent come together, and where the majority of local drainage objections arise. Lincolnshire County Council sets out its role and standards on its managing flood risk pages.

Before you assume a soakaway will work, our free geology and ground conditions map and BRE 365 infiltration rate calculator give an early read, and the drainage calculators help size attenuation. Where the risk is chiefly about how much water leaves the site, a preliminary drainage design flags the problem before it drives the layout, and a full discharge of drainage conditions follows once permission is granted. The generic critical drainage area issues that trip schemes up nationally are sharper here because of the ground.

What East Lindsey's validation list requires

East Lindsey's validation list names flood risk and drainage assessments as supporting documents that an application may need before the council will register it. Submitting without them where they are required is one of the most common reasons an application is delayed at the front door, so it pays to confirm the requirement before you submit rather than after.

Alongside the national requirements — the application form, location and site plans, ownership certificates and the fee — the council's validation page lists flood risk and drainage assessments among the additional documents that a proposal may need depending on its nature and location. On coastal applications the council consults the Environment Agency and works from the Coastal Flood Hazard Map. The practical test is simple: if your site triggers a flood risk assessment or a drainage strategy under the table above, treat that document as part of a valid submission, not something to add later. Our guide to why applications get invalidated on flood risk and drainage covers the traps in detail, and the NPPF guidance sets the national backdrop.

How national policy applies in East Lindsey

National policy sits over the top of the local rules. The National Planning Policy Framework and its Planning Practice Guidance set the sequential, risk-based approach to flood risk; the flood zones and the Flood Map for Planning frame where development can go; and the national SuDS standards shape the drainage. East Lindsey applies all of this through its own policies and evidence base, working from the government's flood risk assessment guidance.

The NPPF steers development towards the lowest flood-risk land first, which is why the sequential test carries real weight in a district with so much land in Flood Zones 2 and 3. Where a site must proceed in a higher-risk area, the exception test and the correct flood risk vulnerability classification have to be argued. On drainage, the 2025 national SuDS standards set the hierarchy every LLFA now works to. Lincolnshire is also trialling new approaches to local flood warning and groundwater monitoring, a sign of how seriously the county takes the sources that fall outside the national systems.

Flood risk in East Lindsey's area

East Lindsey faces both coastal and inland flooding. The tidal North Sea coast, defended by sea walls, dunes and a recharged beach from Mablethorpe down to Skegness, is the dominant risk, while inland the Steeping, Lymn and Witham and a dense network of drains and pumped watercourses across the marsh and fen carry the fluvial and surface-water risk. Groundwater rises through the low ground in wet winters.

The district's defining recent event was the June 2019 Wainfleet flood, when around 138mm of rain fell in three days — roughly double the June average — and the River Steeping's relief channel breached, flooding homes and forcing the evacuation of around 1,000 people across the affected area. It is a reminder that the pumped, defended landscape here works until an extreme event overwhelms it, and that residual risk behind a defence is never zero. For the full local flood-risk picture on the coast we cover it in depth on our area pages for Skegness and Mablethorpe, and across the wider county on our Lincolnshire page.

How Unda helps with flood risk and drainage in East Lindsey

We act as the accurate translation layer between your scheme and the four bodies that decide water in East Lindsey. We are experts on how this district and Lincolnshire's LLFA and drainage boards work, and we prepare the flood risk assessment and the drainage strategy so their cases stay consistent and an objection has nowhere to land.

An East Lindsey report from Unda assesses every credible source — the tidal coast, the Steeping and the other watercourses, surface water and the groundwater that rises through the marsh and fen — sets finished floor levels and safe access against modelled flood levels, and designs a drainage strategy that holds discharge within the LLFA's rate and secures the Internal Drainage Board's consent where the site needs it. We are a CIWEM Business Partner with chartered members, and a senior consultant signs off every report and stays involved to answer the council's and the LLFA's questions.

Flood risk and drainage services for every situation in East Lindsey's area

A flood risk assessment, a sequential or exception test and a drainage strategy are three distinct reports. They often travel together in a planning submission, but they answer different questions: is the site safe, should the development be here, and where does the surface water go. We prepare all three, alongside the right form of assessment for buyers, lenders and BREEAM.

• Flood risk assessment for planning. The core site-specific report, prepared to satisfy the NPPF, the Environment Agency and East Lindsey District Council. Groundwater and, where needed, flood modelling are assessed within it.
• Sequential and exception tests. The separate locational case about whether a development belongs in a higher-risk part of the district at all — often decisive in a district with so much land at risk.
• Surface-water drainage strategy (SuDS). The engineering that holds runoff within Lincolnshire's discharge rate and works with the Internal Drainage Board's consent.
• Groundwater flood risk. A defensible design water table for the fen and marsh and for any below-ground level — assessed within the FRA, or standalone on complex sites.
• Homebuyer and property-purchase survey. For conveyancing, where a search has flagged coastal or surface-water risk and you need the actual building assessed.
• Flood risk assessment for insurance. Property-specific evidence for brokers and underwriters where premiums have risen or cover has been restricted.
• Flood risk assessment for BREEAM. Structured around BREEAM Pol 03, which is credit-driven rather than safety-driven, so a planning FRA alone rarely satisfies it.

East Lindsey flood risk and drainage: frequently asked questions