Flood Risk & Drainage Requirements for Barking and Dagenham

Barking and Dagenham Council applies Policy DMSI 6 (Flood risk and defences) and Policy DMSI 7 (Water management) of the Barking and Dagenham Local Plan 2037, adopted 18 September 2024, alongside London Plan Policies SI 12 and SI 13. The rule that most often reshapes a scheme sits in DMSI 6. A site that the Environment Agency's climate change modelling shows flooding in future is designed as if it were already in that flood zone, and floors near the tidal Thames and Roding are set against a breach of the defences.

So a plot in Flood Zone 1 today can still need raised floors. It may also need a basement rethink and an evacuation plan. On the drainage side, the council is its own Lead Local Flood Authority and has published no local discharge-rate figure. The run-off case for each site is argued instead from DMSI 7, the London Plan drainage hierarchy and the borough's 2017 Strategic Flood Risk Assessment. We prepare flood risk assessments and drainage strategies for applications to Barking and Dagenham Council; to talk through a site, call 01293 214444 or email enquiries@unda.co.uk.

Barking and Dagenham Council and the other bodies that decide on flood risk and drainage

One council holds both local roles. Barking and Dagenham Council decides the planning application and, as Lead Local Flood Authority, advises on its surface water drainage; DMSI 7 asks every applicant to "have regard to advice from the Council as the Lead Local Flood Authority (LLFA)" on sustainable drainage. Planning applications are handled for the council by Be First, its regeneration company, which also runs the validation check. The LLFA role and its legal basis are covered in our guide to the Lead Local Flood Authority.

Where a scheme touches a main river or a tidal defence, the Environment Agency's own consent process runs alongside planning and is not settled by a planning permission. How the Agency responds to applications in the flood zones is explained in our note on the Environment Agency in flood risk planning.

Barking and Dagenham Local Plan flood policies: DMSI 6, DMSI 7 and the London Plan

The 2037 Local Plan puts the flood and drainage tests in two development management policies, DMSI 6 and DMSI 7, with the river buffer zones in DMNE 4 and the borough-wide commitment in Strategic Policy SP7. London Plan Policies SI 12 and SI 13 form part of the same development plan. Both sets apply at once.

Requirements checked November 2026.

Policy DMSI 6 (Flood risk and defences): future flood zones and the SFRA's Section 7

Policy DMSI 6 asks for a flood risk assessment wherever DEFRA and Environment Agency thresholds apply, and for every scheme to leave flood risk from any source no worse, on or off the site. Clause 1 opens: "Development should seek to deliver a neutral impact or reduction in flood risk from any source, on and off-site" (Local Plan 2037).

Clause 2 changes designs most. If a site is outside Flood Zone 2 or 3 today but Environment Agency modelling shows it affected once climate change is assessed, "the same design considerations should be applied as if it was within the present-day Flood Zone". Clause 4 requires development to be placed in the lowest-risk part of the site and "designed in strict accordance with the Development Control recommendations set out in Section 7 of the Strategic Flood Risk Assessment (SFRA) Level 1 Report". Clause 5 rules out basements and any use that is not water compatible in Flood Zone 3b and restricts both in Zones 2 and 3a.

Clause 6 applies only to proposals along the Thames and the tidal River Roding. Those schemes are expected to maintain, repair or replace the defences for the lifetime of the development and set buildings back so the defences can be replaced. They should also seek to raise the walls to the Thames Estuary 2100 levels, or show by plans and cross-sections how that could happen later, improve access, safeguard land for raising and secure partner funding. Clause 7 lets the council ask for a condition survey of the existing defences and watercourse structures to show they will work for the lifetime of the development, with repairs or replacement where they will not.

A floor height set against the defended map instead of the breach level, or a basement in defended Flood Zone 3a with no inundation time, fails clause 4, because Section 7 of the SFRA sets both. How we meet it: our assessment obtains the Agency's modelling and sets floor levels against the SFRA's breach and climate change levels. It states the basement position for the zone and, on a frontage site, the defence works clause 6 lists.

Policy DMSI 7 (Water management): greenfield run-off and the LLFA's advice

Policy DMSI 7 requires every scheme to use permeable surfaces unless that is shown to be unavoidable, and asks that "Development proposals should aim to achieve greenfield run-off rates and ensure that surface water run-off is managed as close to its source as possible in line with Policy SI 13 of the London Plan 2021 and the drainage hierarchy" (Local Plan 2037).

Major development must include SuDS where appropriate, taking account of the national technical standards and the council's SFRA; minor development is expected to include them where feasible. Any SuDS proposal needs "a long-term SuDS Management and Maintenance Plan, including details of who is responsible for maintenance". The permeable surfaces rule in clause 1 reaches front gardens and driveways. Small schemes are caught too. Clauses 5 and 6 add the water side: mains water use cut in line with London Plan Policy SI 5, and early use of Thames Water's free pre-planning service to confirm capacity.

A strategy that jumps straight to a sewer connection, or keeps the brownfield site's existing discharge as the target, does not show what DMSI 7 asks for. How we meet it: the surface water drainage strategy calculates existing and proposed run-off, works through the hierarchy in order and sizes the storage. It also says who will maintain the system, with the Thames Water capacity check recorded where a connection is needed. Our note on why LLFAs object to planning applications covers the faults that cause delay.

Policy DMNE 4 (Water environment): the 16 m and 8 m buffer zones

Policy DMNE 4 is a water environment policy, but clause 1(h) sets a limit every riverside layout has to respect. It requires a naturalised buffer from the top of bank, or from the landward edge of a flood defence and its underground structures, of "at least 16m for tidal watercourses", at least 8 m for fluvial main rivers and ordinary watercourses and at least 5 m around ponds (Local Plan 2037). Buffers exclude development, hard standing, paths and lighting. On the Thames and Barking Creek, that strip is also the land DMSI 6 wants kept free for future defence raising, so our flood risk assessment and drainage layout show both on the same plan.

Policy SP7 (Securing a clean, green and sustainable borough): the strategic flood commitment

Strategic Policy SP7 commits the council to "work with developers and key stakeholders to reduce flood risk (including through the use of Sustainable Drainage Systems)" and to improve wastewater infrastructure (Local Plan 2037). It adds no separate test of its own. A drainage strategy that shows a reduction in run-off, set against the existing site, is the clearest way to show a scheme contributes to it.

London Plan Policy SI 12 (Flood risk management) on the Thames and Roding frontages

Policy SI 12 says "Development proposals should ensure that flood risk is minimised and mitigated, and that residual risk is addressed", and part F requires development next to flood defences to protect their integrity, allow access for maintenance and upgrading and, unless exceptional circumstances are shown, be set back from them (London Plan 2021). In this borough residual risk means a breach of the Thames or Barking Creek walls, which is why the SFRA's breach levels, not the defended flood map, drive floor heights.

London Plan Policy SI 13 (Sustainable drainage): the six-step hierarchy DMSI 7 cites

Policy SI 13 sets out the drainage hierarchy DMSI 7 refers to. Rainwater used as a resource comes first, then infiltration, attenuation in green features and discharge direct to a watercourse; a surface water sewer and, last, a combined sewer follow (London Plan 2021). Part C adds that impermeable surfacing "should normally be resisted unless they can be shown to be unavoidable". On the London Clay that underlies most of Barking and Dagenham, infiltration often fails the test, so the strategy needs the evidence to move down a step.

Plans in preparation: the Local Plan Review and draft London Plan Policy GHR5

No replacement Local Plan has reached a draft. The council's Local Development Scheme (February 2025 update) gives an indicative Local Plan Review timetable: a call for sites in 2027, Regulation 18 and Regulation 19 consultation in 2028, and submission, examination and adoption in 2029. Until then DMSI 6 and DMSI 7 are the policies to meet. They replaced Core Strategy Policy CR4 (Flood management) and Policy BR4 (Water resource management) in September 2024, when the 2037 plan superseded every policy in the 2010 Core Strategy and the 2011 Borough Wide Development Policies.

The Mayor's draft London Plan went out to consultation until 15 October 2026, with examination due in 2027 and adoption in early 2028. On adoption the new London Plan would replace the 2021 Plan, including SI 12 and SI 13. Its flood content sits in draft Policy GHR5 (Flood risk and drainage), which deals with surface water and drainage, and draft Policy GHR9 (Clean and healthy waterways), which covers the riverside aspects of fluvial flood and the defences. Draft GHR5 asks referable schemes to "aim to achieve on-site greenfield run-off rates as measured in Qbar (mean average flood flow) or 3l/s/Ha (whichever is higher)", with off-site contributions where that cannot be met on site (draft London Plan 2026). SI 12 and SI 13 apply until it is adopted.

Which Barking and Dagenham schemes need an FRA, a sequential test or a SuDS strategy

The February 2026 validation checklist and the NPPF set the triggers; DMSI 6 and the SFRA then decide what the reports must contain. A flood risk assessment asks whether the site is safe, a sequential or exception test whether the development should be there at all, and a drainage strategy where the water goes. They are separate reports, even when they go in together.

Our guide to the sequential and exception tests explains how sites are compared, and the flood zones explainer sets out what each zone means. For a first read of a postcode's river, sea and surface water risk before a report is commissioned, use our flood risk map or the Environment Agency's Flood Map for Planning.

Breach levels, floor heights and basements: what the 2017 SFRA sets

The borough's Level 1 Strategic Flood Risk Assessment (version 8.0, August 2017, WSP Parsons Brinckerhoff) is the evidence behind DMSI 6, and its Section 7 is written into the policy. A Level 2 SFRA of the same date covers the strategic regeneration sites and applies the Exception Test to them. No newer SFRA has been published; the Local Development Scheme lists fresh evidence work for 2026 and 2027.

• Floor levels. At least 0.3 m above the 1 in 100 year fluvial level with climate change; in tidal areas, the 1 in 200 year level with climate change "calculated assuming a breach of the raised flood defences". A freeboard of 0.6 m is recommended where levels are uncertain or the use is highly vulnerable (paragraph 7.6.4).
• Surface water. Floors at whichever is higher of 0.3 m above ground or 0.3 m above the estimated flood depth, with climate change (7.6.5).
• Time to flood. Where floors in defended Flood Zone 3a cannot clear the breach level, the SFRA recommends slowing inundation to 10 hours or more to allow evacuation (7.6.8). Our flood warning and evacuation plans set out the safe route and the trigger to leave.
• Basements. Not acceptable in Flood Zone 3b, and no habitable or more vulnerable basements in undefended Flood Zone 3a. Less vulnerable basements are acceptable in defended Zone 3a only where a breach takes longer than 5 hours to flood them, with access 0.3 m above the design level (7.6.9 to 7.6.11).
• Functional floodplain. Flood Zone 3b is land flooding at a 1 in 20 or greater annual chance, or land designed to flood in a 1 in 1,000 event. Because the rivers are well defended, it is generally confined to the channels and the land between channel and defences (5.2.3 to 5.2.5).
• Climate change. The SFRA predates the Environment Agency's current climate change allowances (last updated May 2022), so our assessments apply the current allowances rather than the 2016 figures the SFRA used.

Breach levels come from Environment Agency modelling. The national flood map does not show them, and our explainer on what Strategic Flood Risk Assessments contain explains how an SFRA feeds a site report. The SFRA also maps increased potential for elevated groundwater, which matters for basements on the river terrace gravels; our groundwater assessments cover it inside the flood risk assessment.

The February 2026 validation checklist and the SuDS proforma

The council's Full Planning Applications Checklist of February 2026, listed on its validation checklists page, asks for a flood risk assessment for "Developments of one hectare or greater in Flood Zone 1" and "All development proposals located in Flood Zones 2 and 3", with a sequential and exception test where appropriate. A Sustainable Drainage Strategy and Sustainable Drainage Proforma are required 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". Without them the application is not validated. The checklist still refers to the NPPF's former chapter numbering; the tests now sit in Chapter 18.

The council's proforma template links to the London Sustainable Drainage Proforma, which has a Barking and Dagenham version on the Mayor's website. It is a validation item for the schemes above, not for every application. The July 2026 householder checklist has no drainage item, though a householder extension in Flood Zone 2 or 3 still needs a flood risk assessment under national policy. Our SuDS proforma guide explains how it is filled in, and our note on planning applications invalidated over flood risk or drainage covers what happens when an item is missing.

Drainage standards the council applies as Lead Local Flood Authority

Barking and Dagenham has no SuDS design guide of its own. Its standards come from DMSI 7, the SFRA and national policy, and there is no local discharge figure to quote. The points a drainage strategy for a major scheme has to cover are below.

• Discharge rate. DMSI 7 asks schemes to aim for greenfield run-off. The SFRA (7.7.19) limits greenfield sites to existing rates for every event from 1 in 1 to 1 in 100 years. Brownfield sites go as far as practical towards the greenfield rate and never above the rate before redevelopment, and the council may require greenfield rates in catchments that add to flooding downstream (SFRA Level 1).
• Volume. For the 1 in 100 year, 6 hour storm, run-off volume from a greenfield site should not exceed the greenfield volume, and from a brownfield site should be held as close to it as practical (7.7.20).
• National Standards. NPPF policy F8 now asks for SuDS designed to the National Standards for Sustainable Drainage Systems; our explainer on the 2025 National Standards for SuDS sets out what changed. The council has issued no statement of its own on applying them.
• Infiltration. London Clay lies under all of the borough except the far south, so soakaways often fail; tests to BRE Digest 365 at the proposed depth decide it. Our BRE 365 infiltration rate calculator, ground conditions checker and drainage calculators give an early read.
• Climate change. Peak rainfall uplift from the Environment Agency's climate change allowances, with the development lifetime stated.
• Maintenance. A long-term SuDS management and maintenance plan naming who is responsible, as DMSI 7(4) requires.
• Capacity. Early use of Thames Water's free pre-planning service to confirm sewer capacity (DMSI 7(6)), recorded in the strategy (Thames Water).
• Critical drainage areas. The council's 2011 Surface Water Management Plan defines local critical drainage areas; the SFRA notes there are no Environment Agency designated ones (4.4.2). Our note on critical drainage areas in planning explains why a minor scheme in one needs a SuDS strategy.

Where a scheme is consented with a drainage condition, the discharge of drainage conditions work takes the approved strategy to the detail the condition asks for.

Chapter 18 of the NPPF on a Barking and Dagenham application

National policy sits under the local plan in Chapter 18 of the National Planning Policy Framework (August 2026). Policy F4 asks for a site-specific flood risk assessment for all development in Flood Zones 2, 3a and 3b. In Flood Zone 1 it applies to sites of 1 ha or more, land with critical drainage problems and land the SFRA or Flood Map for Planning shows at risk from any source, now or in the future, which matches DMSI 6's climate change rule. Policy F5 applies the sequential test to risk from any source, with exemptions for allocated sites, householder development, small non-residential extensions and most changes of use. F6 sets the exception test, F7 requires development to be safe for its lifetime with residual risk managed, and F8 covers SuDS. The Planning Practice Guidance on flood risk was last updated in September 2025. Our NPPF guidance service explains how these tests apply to a site.

Tidal Thames, Roding, Beam and surface water: the borough's flood risk in brief

The borough's south lies on the north bank of the tidal Thames downstream of the Thames Barrier, behind raised walls. The Thames Estuary 2100 policy unit for Barking and Dagenham is P4: the Environment Agency will act to keep risk from rising, defence owners should raise defences where needed by 2040, and councils should plan their riverside by 2030. The Roding forms the western edge and is tidal for 9 km above the Barking Barrier at Creekmouth, which closes against surge tides. On the eastern edge the Beam River has the Beam Washlands to store flood water, and Mayes Brook has its own storage. Our River Thames page covers the wider tidal river.

Surface water is now the larger share of the risk. The Mayor's London Regional Flood Risk Assessment (March 2026) puts 14% of the borough's land at high risk of surface water flooding, the third-highest share in London. Dagenham Heathway has 51% of its town-centre land at high surface water risk, more than any other London town centre. The SFRA records flooding across the borough in June 2016, mainly to roads with some homes flooded internally. For the town centre, Creekmouth and Barking Riverside, see our page on flood risk assessment in Barking; London-wide policy is on our London flood risk page, and other boroughs are listed under local authorities.

Reports we prepare for Barking and Dagenham planning applications

Each service below answers a Barking and Dagenham requirement, from the DMSI 6 breach levels to the DMSI 7 run-off case.

• Flood risk assessments. Every DMSI 6 scheme starts by assessing all sources of flooding; our flood risk assessment work covers each type.
• Planning applications. Sites in Flood Zones 2 and 3, sites of 1 ha or more and land the climate change modelling puts at risk need a flood risk assessment for planning with SFRA Section 7 levels.
• Buying a property. A tidal Flood Zone 3 search result on a Thames View or Creekmouth home calls for a flood risk survey for property purchase.
• Sequential and Exception Tests. New homes in Flood Zones 2 and 3 outside the plan's allocations need the sequential and exception test before DMSI 6(3) is met.
• Drainage Strategy. DMSI 7 makes SuDS part of every major scheme, set out in a drainage strategy.
• Surface Water Drainage Strategy. The February 2026 checklist asks for a SuDS strategy and proforma, which a surface water drainage strategy provides.
• Discharge of Drainage Planning Conditions. Drainage conditions on consents are cleared through discharge of drainage conditions.
• Flood warning and evacuation. SFRA 7.6.8 ties defended Flood Zone 3a schemes to evacuation time, which a flood warning and evacuation plan sets out.
• Groundwater. Basements on the terrace gravels need the SFRA's elevated groundwater mapping read as part of a groundwater assessment.
• Due diligence. Industrial land at Dagenham Dock and along Thames Road sits behind the tidal walls, where buyers and lenders commission commercial due diligence.
• Insurance. Homes flooded in June 2016 and those in tidal Flood Zone 3 can face higher premiums; an insurance flood risk assessment gives the insurer site evidence.
• National policy. Our NPPF guidance applies Chapter 18 to the site alongside the Local Plan.

Our consultants are chartered, and every report is written to the Barking and Dagenham policy it has to satisfy. Reports for applications to Barking and Dagenham come from Unda Consulting Limited, a CIWEM Business Partner. Call 01293 214444 or email enquiries@unda.co.uk for a fixed fee quote.

Questions about Barking and Dagenham's flood and drainage requirements