Flood Risk Assessment in Barking and Dagenham

Barking and Dagenham Council decides planning applications against its own 2037 Local Plan, adopted on 18 September 2024, and it expects flood risk and drainage evidence to be dealt with together, not as two separate afterthoughts. Most schemes in Flood Zone 2 or 3, sites of a hectare or more, and any major development need a flood risk assessment, a surface water drainage strategy, or both — submitted alongside the borough's mandatory London Sustainable Drainage Proforma.

We prepare flood risk assessments and drainage strategies for developments across Barking and Dagenham's area for planning, property purchase, mortgage and insurance, and BREEAM assessment, alongside sequential and exception tests, groundwater assessment and flood modelling. A flood risk assessment, a sequential or exception test and a drainage strategy are three distinct reports that answer three different questions: is the site safe, should the development be here, and where does the surface water go.

Barking and Dagenham's Local Plan treats climate-change flood extents as today's risk, not a future scenario — so an application has to satisfy Policy DMSI 6 against that tougher baseline, whatever the current Flood Map for Planning happens to show for the site.

• Who decides: Barking and Dagenham Council is both the local planning authority and the Lead Local Flood Authority (LLFA) for its area.
• Adopted Local Plan: the Barking and Dagenham 2037 Local Plan, adopted 18 September 2024 — the current statutory development plan.
• Flagship policies: Policy DMSI 6 (flood risk and defences) and Policy DMSI 7 (water management).
• Strategic Flood Risk Assessment: Level 1 and Level 2 SFRA, both by WSP | Parsons Brinckerhoff, dated August 2017.
• Drainage expectation: greenfield run-off rates in line with London Plan Policy SI13, source control, and a SuDS Management and Maintenance Plan on major development — the council has not published its own numeric discharge-rate floor.
• Validation: the London Sustainable Drainage Proforma is mandatory for major applications, per the council's Full Planning Applications Checklist (February 2026).

Who decides flood risk and drainage in Barking and Dagenham?

Barking and Dagenham Council performs both roles that matter to a developer: it is the local planning authority that determines the application, and it is the Lead Local Flood Authority (LLFA), the statutory consultee on surface water drainage for major development under the Flood and Water Management Act 2010. That single-body arrangement is standard for London boroughs, but it is worth stating plainly, because in two-tier areas elsewhere in England a district council and a county council split these functions and applicants often assume the same split applies here. It doesn't. Policy DMSI 7 of the adopted Local Plan explicitly directs applicants to "have regard to advice from the Council as the Lead Local Flood Authority" — the same planning department, wearing a second hat.

• Local planning authority: Barking and Dagenham Council, with planning services delivered through Be First on the council's behalf.
• Lead Local Flood Authority: Barking and Dagenham Council — the statutory consultee on surface water drainage for major applications.
• Environment Agency: covers the tidal Thames, the River Roding and the borough's other main rivers, and is consulted on Flood Zone 2/3 and functional floodplain issues.
• Internal Drainage Board: none covers Barking and Dagenham — there is no separate IDB consenting regime to factor in here, unlike parts of eastern England.

Understanding what an LLFA actually does and how councils balance planning and drainage responsibilities under the Flood and Water Management Act helps explain why a Barking and Dagenham application needs both flood risk and drainage evidence addressed from the outset, not bolted on after an objection.

Does a Barking and Dagenham application need a flood risk assessment or drainage strategy?

A flood risk assessment is required for any development in Flood Zone 2 or 3, for sites of one hectare or more in Flood Zone 1, and increasingly for smaller Flood Zone 1 sites the Flood Map for Planning shows to be at risk of surface water. A drainage strategy and the London Sustainable Drainage Proforma are required for major development and for smaller schemes likely to affect surface water run-off. Barking and Dagenham's own Full Planning Applications Checklist (February 2026) sets out both triggers in full.

Missing either document is one of the most common reasons an application is invalidated rather than refused — the clock never starts until the council has what its checklist asks for. Our guide on why planning applications get invalidated for flood risk or drainage and our explainer on when a flood risk assessment is required cover the wider national picture behind Barking and Dagenham's local checklist.

Barking and Dagenham's drainage and SuDS requirements

Policy DMSI 7 expects development to achieve greenfield run-off rates in line with London Plan Policy SI13, manage surface water as close to its source as possible, and incorporate sustainable drainage systems on all major development. What the council has not published is its own numeric discharge-rate floor or a stated brownfield betterment percentage, so schemes have to build their case on the London Plan's drainage hierarchy, CIRIA guidance and the site's own runoff calculations rather than quoting a single local figure back at the LLFA.

• Drainage hierarchy: infiltration first, then discharge to a watercourse, then a surface water sewer, then a combined sewer only as a last resort.
• London Sustainable Drainage Proforma: mandatory at validation for major applications, via the Greater London Authority — every London borough, Barking and Dagenham included, requires it alongside the drainage strategy itself.
• Infiltration evidence: where a scheme proposes soakaways, BRE 365 infiltration testing is expected before the council will accept an infiltration-based strategy — much of the borough sits on London Clay, so testing rather than assumption is the safer route.
• SuDS Management and Maintenance Plan: Policy DMSI 7 requires a long-term maintenance plan naming the party responsible for the SuDS scheme for the lifetime of the development.
• Water efficiency: development is expected to minimise mains water use in line with London Plan Policy SI5, with early engagement with Thames Water on wastewater capacity.

Because no bespoke Barking and Dagenham discharge-rate document has been published, the safest position for an applicant is to treat the London Plan hierarchy as the starting point and evidence every figure rather than assume the LLFA will accept a generic industry rate. Our guides to what a SuDS proforma is and when it's required, BRE365 infiltration testing and the common reasons an LLFA objects set out how to build that evidence before submission, and our free drainage calculators and geology and ground conditions checker give a fast first read on infiltration feasibility ahead of a trial pit.

Barking and Dagenham's Local Plan flood and drainage policies

The Barking and Dagenham 2037 Local Plan carries two policies that between them govern almost every flood risk and drainage decision in the borough. Policy DMSI 6 handles flood risk and defences; Policy DMSI 7 handles water management and drainage. Both superseded the borough's older 2010 and 2011 policies when the new plan was adopted, and no emerging replacement plan is currently under examination.

Policy DMSI 6 — flood risk and defences

Policy DMSI 6 requires a flood risk assessment for development meeting national DEFRA and Environment Agency thresholds, and it insists the assessment treat climate-change-projected flood extents as the present-day risk rather than a distant scenario. It cross-refers to the NPPF's sequential and exception test, requires design to follow the recommendations in Section 7 of the borough's SFRA Level 1, and rules out basements and other non-water-compatible uses in Flood Zone 3b. Where a site sits near the tidal Thames or the River Roding, the policy also expects defence maintenance, appropriate setback, and — for some schemes — a financial contribution towards raising defences to Thames Estuary 2100 standards.

Policy DMSI 7 — water management

Policy DMSI 7 requires new development to manage surface water sustainably, aiming for greenfield run-off rates calculated in line with London Plan Policy SI13 and dealt with as close to its source as possible. Major development must incorporate sustainable drainage systems, have regard to the council's SuDS guidance, and be accompanied by a SuDS Management and Maintenance Plan naming the party responsible for the scheme's upkeep. The same policy expects development to minimise mains water demand under London Plan Policy SI5 and to engage Thames Water early on wastewater capacity — a step easy to overlook until a capacity objection arrives late in determination.

Both policies replaced the borough's 2010 Core Strategy Policy CR4 (flood management) and the 2011 Borough Wide Development Policies DPD Policy BR4 (water resource management), which the 2024 Local Plan formally supersedes. There is currently no emerging Local Plan review in preparation, so DMSI 6 and DMSI 7 remain the policies to satisfy for the foreseeable future.

Barking and Dagenham's Strategic Flood Risk Assessment

Barking and Dagenham has its own Strategic Flood Risk Assessment rather than relying on a joint pan-London document — a Level 1 and a Level 2, both prepared by WSP | Parsons Brinckerhoff and dated August 2017. The SFRA is the evidence base behind Policy DMSI 6, and it defines the functional floodplain (Flood Zone 3b) locally as effectively contained behind the borough's Thames and Roding tidal defences, rather than a widespread constraint across the borough. It states plainly that there are no Environment Agency-designated Critical Drainage Areas in Barking and Dagenham, although the SFRA itself identifies locally-derived critical drainage areas from the 2011 Surface Water Management Plan for its own internal use.

• Level 1 and Level 2 SFRA: both by WSP | Parsons Brinckerhoff, dated August 2017.
• Functional floodplain: defined by the SFRA as behind the borough's tidal defences rather than a widespread constraint.
• Critical Drainage Areas: no EA-designated CDAs in the borough; the SFRA references locally-derived areas from the 2011 Surface Water Management Plan.
• Climate change allowances: the SFRA applies the February 2016 Environment Agency bands — check the current EA climate change allowances guidance directly, since no confirmed SFRA update has been published since 2017.

What Barking and Dagenham's validation checklist requires

The council's Full Planning Applications Checklist (February 2026) sets the local threshold for what has to accompany an application before it will be registered. For flood risk, that means a flood risk assessment for "developments of one hectare or greater in Flood Zone 1" and for "all development proposals located in Flood Zones 2 and 3" — standard national triggers, with no additional local numeric threshold layered on top. For drainage, it requires a SuDS strategy for "major development" and for "minor development which is likely to have an adverse impact on surface water run-off or is in a critical drainage area," together with the LBBD SuDS Proforma template, which links directly to the Greater London Authority's London Sustainable Drainage Proforma.

• FRA trigger: Flood Zones 2 and 3 (any scale); Flood Zone 1 sites of one hectare or more.
• SuDS strategy trigger: major development, or minor development with a likely adverse surface-water impact or in a critical drainage area.
• SuDS proforma: the council's own template routes directly to the pan-London GLA proforma — this is the same document required across every London borough.
• "Major development": the standard national thresholds apply — 10 or more dwellings, 1,000m² or more of floorspace, or a site of one hectare or more.

An incomplete or last-minute proforma is one of the most common reasons drainage gets flagged at validation. Our guide to the SuDS proforma and when it's required and our explainer on what drainage information planning permission conditions actually ask for both cover how to get this right the first time rather than after an invalidation notice.

How national flood and drainage policy applies in Barking and Dagenham

Barking and Dagenham's local policies sit on top of the national framework, and both layers now have to be satisfied together. The NPPF's sequential test steers development to the lowest flood-probability land available before anything is approved in a higher-risk zone, and since the September 2025 Planning Practice Guidance update that risk-based approach applies to all sources of flooding, not just rivers and the sea — surface water and groundwater are explicitly in scope. The 2025 National Standards for Sustainable Drainage Systems add an interception target for the first millimetres of rainfall and require every scheme to address all four SuDS objectives: water quantity, water quality, amenity and biodiversity. Barking and Dagenham Council's own duties as LLFA — consulted on surface-water drainage for major development, and required to co-operate with other risk management authorities — trace back to the Flood and Water Management Act 2010, the legislation that followed the 2007 floods.

Our guides to how the NPPF applies to flood risk, the sequential and exception tests, the 2025 National Standards for SuDS and the Flood and Water Management Act 2010 set out the national scaffold that DMSI 6 and DMSI 7 sit on top of.

Flood risk in Barking and Dagenham, in brief

Barking and Dagenham's flood risk is dominated by tidal exposure on the Thames and Barking Creek, fluvial risk from the River Roding along the western boundary and the River Beam and its tributaries further east, and surface water — the risk type now the most widespread across England. The Barking Barrier protects Barking Creek, the tidal mouth of the Roding, as part of the wider Thames tidal defence network; the Beam Washlands and Mayes Brook flood storage areas provide fluvial attenuation further inland. No dated historic flood event for the borough could be independently verified for this page, and no Planning Inspectorate appeal decision citing flood or drainage grounds in Barking and Dagenham was identified — so neither is asserted here.

The borough's flood and drainage requirements are being tested at scale by Barking Riverside, a major regeneration scheme now the subject of a new outline application (ref. 24/01141/OUTALL) targeting around 20,000 homes on former industrial land along the Thames. The scheme's own material describes a sitewide flood risk and drainage strategy with attenuation along the foreshore and controlled discharge to the Thames agreed with the Environment Agency and the Port of London Authority — a useful illustration of how DMSI 6 and DMSI 7 are applied on the borough's largest sites.

The full local flood-risk picture — historic events, named watercourses and ward-level detail — is best read directly from the Thames Estuary 2100 Barking and Dagenham Policy Unit and the check-for-flooding service for the borough, alongside our own free flood risk map and live river levels map for a quick postcode-level read before commissioning a site-specific assessment.

How Unda helps with flood risk and drainage in Barking and Dagenham

We have extensive experience preparing flood risk assessments and drainage strategies against London borough planning policy, including the two-hat LPA/LLFA structure and the mandatory London Sustainable Drainage Proforma that Barking and Dagenham shares with every other London borough. Our flood risk consultants work from Barking and Dagenham's own Local Plan, SFRA and validation checklist rather than generic national templates, so the evidence submitted answers what DMSI 6 and DMSI 7 actually ask for.

Whether the need is a flood risk assessment for a planning application, a surface water drainage strategy, or help discharging a drainage-related planning condition, our flood risk consultants prepare policy-compliant reports built around the specific council and LLFA a scheme has to satisfy.

Flood risk and drainage services for every situation in Barking and Dagenham's area

Planning applications are one reason to need flood risk and drainage evidence in Barking and Dagenham, and property purchase, insurance and BREEAM assessment are just as real. Each is a distinct service, built for a different audience and a different question.

• Flood risk survey for property purchase: a homebuyer flood risk survey for a property transaction where a search or lender has raised a flag.
• Flood risk assessment for insurance: an insurance-focused assessment where premiums have risen or cover has been restricted.
• BREEAM flood risk assessment: a BREEAM Pol 03 assessment, structured differently from a planning FRA because BREEAM credits are based on pre-development risk classification.
• Sequential and exception tests: the locational justification report asking whether a lower-risk site was reasonably available.
• Groundwater assessment: a dedicated look at groundwater as a flood source that appears on no national flood map and is governed by local geology.
• Flood modelling: hydraulic modelling brought in where national mapping alone is not enough to establish accurate flood levels, extents and flows.
• Discharge of drainage conditions and preliminary drainage design: detailed drainage design to satisfy a planning condition, or a preliminary drainage design at outline stage.

Frequently asked questions