BREEAM V7 Flood Risk Credits | Enhanced Climate Resilience Requirements

BREEAM Version 7 introduces the most significant changes to flood risk assessment since the scheme's inception, transforming flood credits from optional additions to mandatory requirements for Excellent and Outstanding ratings. Projects registered from January 2025 onwards face substantially higher expectations for climate resilience, with stricter minimum standards, enhanced climate change factors, and more demanding evidence requirements.

The philosophical shift underlying these changes reflects growing understanding of climate risk. Version 6 treated flood risk as one environmental issue among many, allowing projects to compensate for weak flood performance through credits elsewhere. Version 7 recognises that buildings in inappropriate flood locations or without proper resilience measures represent fundamental failures of sustainable development, regardless of performance in other categories.

For developers and design teams, this means flood risk assessment can no longer be left to planning stage compliance exercises. Site selection, building positioning, finished floor levels, access arrangements, and resilience strategies now directly determine achievable BREEAM ratings. Sites that easily reached Outstanding under Version 6 may struggle to achieve Excellent under Version 7 without substantial additional investment in flood protection.

Overview of Version 7 Flood Risk Changes. BREEAM V7 flood risk

BREEAM V7 flood risk credits continue assessing developments based on Environment Agency flood zone classifications, but with critical enhancements across assessment methodology, climate change assumptions, and resilience specifications.

Key Changes Summary:

Mandatory Minimum Standards: Excellent rating requires minimum 1 flood risk credit, Outstanding requires minimum 2 credits. Previously, no minimum standards existed—projects could score zero flood credits and still achieve Outstanding through other categories.

Enhanced Climate Change Allowances: Default climate change factor increases from +40% to +45% peak flows for 2080s scenarios across most of England. Higher central estimates become the standard assumption, not central estimates.

Surface Water Flood Mapping: Assessment must explicitly include updated 2024 surface water flood maps alongside traditional fluvial mapping. Surface water flooding now affects more properties than river flooding in England—ignoring it means incomplete assessment.

Groundwater Flooding Consideration: Explicit requirement to assess groundwater flood susceptibility using British Geological Survey data and local authority evidence. Previous versions mentioned groundwater but didn't mandate assessment.

Enhanced Resilience Specifications: Both 600mm freeboard and BS 8533 compliance routes include additional requirements addressing access, refuge, recovery time, and cumulative flood impacts—areas frequently overlooked in Version 6 assessments.

Longer Assessment Timeframes: Flood risk must be assessed through building design life (minimum 60 years for most buildings, 120 years for critical infrastructure), not just current conditions or planning policy horizons.

Operational Resilience Requirements: New emphasis on how buildings remain functional during and after flood events, not just whether they survive flooding physically.

These changes reflect updated climate science, lessons from recent flood events (2020s saw record flooding across UK), and recognition that previous standards underestimated long-term flood risk.

Credit Structure and Thresholds Version 7

Version 7 maintains the basic three-tier structure based on flood zones but with substantially enhanced requirements at each level.

Two Credits - Low Flood Risk Sites (Flood Zone 1)

Threshold: Development located in Environment Agency Flood Zone 1 with comprehensive flood risk assessment demonstrating low risk from all sources throughout building life.

Requirements for 2 Credits:

Site-Specific Flood Risk Assessment covering:

All flood sources assessed:

• Fluvial flooding from rivers and watercourses

• Pluvial (surface water) flooding from rainfall exceeding drainage capacity

• Groundwater flooding from rising water tables

• Sewer flooding from overwhelmed drainage infrastructure

• Coastal flooding if within 10km of coast (including estuary)

• Reservoir failure if within flood inundation zone

Each source requires individual assessment—cannot rely solely on EA Flood Map for Planning showing Zone 1. The maps show fluvial and coastal flooding only. Your FRA must address all other sources separately.

Climate change allowances applied:

For 2080s scenarios (60-year building life from 2025):

England (most catchments): +45% peak flows for rivers, +40% peak rainfall intensity for surface water

Upland catchments: +50% peak flows

Small, rapidly responding catchments: +50% peak flows

Coastal locations: +15mm sea level rise per decade

These represent "higher central" estimates from Environment Agency guidance. Version 6 typically applied "central" estimates (+35-40%). Version 7 mandates the more precautionary assumption.

Surface water flood maps (2024 update) reviewed:

The 2024 updated surface water flood maps show significantly more properties at risk than previous 2013 mapping. Your FRA must:

• Review updated maps for 1-in-30, 1-in-100, and 1-in-1000 year events

• Identify flow paths across site from surface water flooding

• Assess whether site levels, access routes, or services vulnerable

• Consider cumulative risk (surface water flooding whilst river levels also elevated)

Many sites showing as Zone 1 for fluvial flooding have medium/high surface water flood risk. This doesn't prevent achieving 2 credits but requires demonstrating adequate mitigation.

Groundwater flooding susceptibility assessed:

Review British Geological Survey groundwater flooding susceptibility maps and local authority data. Assessment must consider:

• Geology and aquifer characteristics

• Historical groundwater flood records

• Proximity to groundwater-dependent features (springs, baseflow rivers)

• Site drainage design preventing groundwater ingress to buildings

• Foundation design considering high groundwater levels

Sites in chalk or limestone with shallow aquifers require particular attention—groundwater flooding can occur even in fluvial Flood Zone 1 areas.

Development lifetime flood risk:

Version 7 requires projecting flood risk through entire building life:

• Residential: 60 years minimum (to 2085 for buildings completed 2025)

• Commercial offices: 60 years minimum

• Industrial: 60 years minimum

• Critical infrastructure (hospitals, emergency services): 120 years (to 2145)

Climate change allowances must cover this full period. For critical infrastructure, this may require upper-end climate scenarios (+70% peak flows) rather than higher central (+45%).

Evidence package must include:

• Topographic survey showing site levels relative to flood levels

• Hydraulic modelling if site near watercourses

• Surface water flow path analysis

• Demonstration that site will remain Zone 1 through building life

• Consideration of climate change impacts on all sources

• Assessment of cumulative flood risks

What Prevents Achieving 2 Credits:

Sites in Flood Zones 2 or 3 cannot achieve 2 credits under any circumstances—maximum achievable is 1 credit with exceptional resilience measures.

Sites showing surface water flood risk across >25% of site area may require demonstrating resilience measures even if fluvial Zone 1, potentially reducing to 1 credit rather than 2.

Sites with identified groundwater flooding without mitigation may reduce to 1 credit even if fluvial Zone 1.

One Credit - Medium/High Flood Risk with Comprehensive Resilience

Threshold: Development in Flood Zones 2 or 3 (not functional floodplain) implementing comprehensive flood resistance and resilience strategy demonstrating acceptable residual risk.

Requirements for 1 Credit:

All requirements for 2 credits (comprehensive FRA, all sources, climate change) PLUS specific resilience measures through either Option A (freeboard) or Option B (BS 8533 strategy).

Option A: 600mm Freeboard Route

Finished floor levels designed:

All habitable floors positioned minimum 600mm above design flood level for site's flood zone:

• Zone 2: 600mm above 1-in-100 year flood level + climate change (+45%)

• Zone 3: 600mm above 1-in-100 year flood level + climate change (+45%)

Design flood level determined through:

• Environment Agency modelling data

• Hydraulic modelling by competent flood risk consultant

• Historical flood levels adjusted for climate change

• Local authority flooding records

Where EA specifies more onerous local requirements, apply those instead. Some high-risk areas require 750mm or 900mm freeboard.

Version 7 Enhancement - Access Routes:

Not just building thresholds—all essential access must achieve 600mm freeboard:

• Pedestrian access from public highway to building entrance

• Vehicle access for service vehicles and emergency access

• Parking areas for operational vehicles (refuse trucks, deliveries)

• Evacuation routes from building to safe refuge areas

This is significantly more demanding than Version 6, which focused primarily on building threshold. Many sites can elevate buildings but struggle with access requiring extensive ramps or impractical gradients.

Version 7 Enhancement - Safe Refuge:

For buildings where evacuation during floods may not be possible (hospitals, care homes, hotels), design must include:

• Safe refuge areas above design flood level + 600mm

• Refuge areas sized for maximum occupancy

• Emergency supplies accessible in refuge areas (water, food, medical)

• Communication systems functional during flooding

• Emergency power for critical systems above flood level

Version 7 Enhancement - Emergency Access:

Emergency vehicle access must remain passable during design flood event:

• Fire tender access routes no deeper than 300mm flooding

• Ambulance access routes no deeper than 200mm flooding

• Alternative access arrangements if primary routes flood

• Coordination with emergency services confirming access adequacy

This addresses lessons from recent floods where buildings survived but emergency services couldn't access them during events.

Version 7 Enhancement - Services Protection:

All building services must be positioned or protected appropriately:

• Electrical intake and distribution boards above flood level + 600mm

• Gas meters and pipework above flood level (or non-return valves fitted)

• Communications infrastructure above flood level

• Heating plant above flood level or with flood-resistant enclosures

• Drainage with non-return valves preventing backflow

Cannot simply position everything at minimum 600mm—must demonstrate services remain functional, not just survive inundation.

Option B: BS 8533:2017 Flood Resilience Strategy

Alternative to 600mm freeboard for sites where elevation isn't feasible (constrained urban sites, conservation areas, sites where access gradients would be excessive).

BS 8533 Hierarchy Approach:

Strategy must follow hierarchy:

1. Avoidance: Position critical functions above flood level where possible

2. Resistance: Prevent water entering building through flood-resistant construction

3. Resilience: Allow controlled flooding but enable rapid recovery

4. Reversion: Emergency measures only where other approaches insufficient

Version 7 Enhancement - Resistance Measures:

Where resistance approach selected, strategy must specify:

• Flood-resistant external doors (tested to BS 851-2 standard)

• Airbrick covers (automatic or deployable)

• Sealed cable and pipe penetrations through walls

• Impermeable render or cladding to design flood level + 300mm

• Window flood boards where windows below flood level

• Perimeter flood barriers where appropriate

All measures must be either passive (automatic, always in place) or deployable with sufficient warning time. Measures requiring >12 hours to deploy aren't acceptable for flash flood areas.

Version 7 Enhancement - Resilience Measures:

Where controlled flooding accepted (resilience approach):

• Solid concrete floors (no suspended timber)

• Lime mortar pointing allowing drying (not cement)

• Water-resistant wall finishes to flood level + 300mm (cement render, dense blockwork)

• Kitchens/bathrooms specified with flood-resilient fittings

• Services routing protected or elevated

• Drainage preventing sewage backflow

• Materials enabling rapid drying without replacement

Strategy must demonstrate building can be reoccupied within agreed timeframe (typically 6 months for residential, 3 months for commercial).

Version 7 Enhancement - Recovery Time Modelling:

New requirement to model and specify recovery time after flooding:

For residential buildings: Maximum 6 months from flood event to reinstatement

For commercial buildings: Maximum 3 months to operational functionality

For critical infrastructure: Maximum 1 month to basic functionality

Modelling must consider:

• Time to dry building fabric (depends on construction type, materials)

• Availability of replacement materials and equipment

• Contractor availability during widespread flooding (many properties affected simultaneously)

• Planning/building control approval timeframes

• Insurance claim processing

Cannot simply state "resilient materials specified" without demonstrating recovery timeframes are achievable.

Version 7 Enhancement - Cumulative Flood Impacts:

Strategy must consider multiple floods in short periods:

• Materials must withstand multiple flood events without degradation

• Drying systems must cope with limited drying time between events

• Cannot rely on one-time sacrificial measures

• Maintenance and inspection regime ensuring continued effectiveness

This reflects recent experience where properties flooded multiple times in single winter (2019-20, 2020-21).

Evidence Requirements for BS 8533 Approach:

• Complete flood resistance and resilience strategy document

• Material specifications with manufacturer flood resistance certifications

• Installation details for all flood protection measures

• Maintenance and inspection schedule

• Building user guide explaining flood response procedures

• Recovery plan with timeframes and contractor arrangements

Competent Professional Requirement:

Both 600mm freeboard and BS 8533 approaches require design and certification by competent professional:

• Chartered engineer with flood risk specialism (ICE, CIWEM, IStructE)

• Demonstrable experience with flood resilience design

• Professional indemnity insurance >£5 million

• Familiarity with BS 8533, EA guidance, and local planning requirements

Cannot rely on architect or general civil engineer without specific flood risk expertise.

Zero Credits - Inappropriate Development

Developments achieving zero flood risk credits include:

Functional Floodplain (Flood Zone 3b):

• Cannot achieve any credits unless water-compatible development only

• Typically prevents BREEAM Outstanding or Excellent ratings due to minimum standards

• Very limited building types acceptable in Zone 3b under planning policy

Flood Zone 2/3 without adequate resilience:

• Sites where neither 600mm freeboard nor BS 8533 strategy implemented

• Inadequate FRA not covering all sources or climate change

• Access routes remaining below flood levels

• Services not properly protected

Inadequate climate change allowances:

• Applying central (+35%) rather than higher central (+45%) estimates

• Not projecting through full building life (60+ years)

• Ignoring surface water or groundwater flooding

Poor quality FRA:

• Desktop only without site-specific hydraulic assessment

• Missing flood sources in assessment

• No consideration of cumulative risks

• Inadequate topographic survey

Zero credits doesn't prevent BREEAM Pass or Good ratings, but Excellent requires 1 credit minimum, Outstanding requires 2 credits minimum. Sites achieving zero credits cannot reach these higher ratings regardless of performance elsewhere.

Minimum Standards for Excellent and Outstanding

Version 7's most significant change is introducing mandatory flood risk credits at higher rating levels.

For Excellent Rating:

Minimum 1 flood risk credit required

This means:

• Cannot achieve Excellent in Flood Zone 3b (functional floodplain) under any circumstances

• Sites in Zones 2 or 3 must implement comprehensive resilience (600mm freeboard OR BS 8533) to reach Excellent

• Sites in Zone 1 must complete robust FRA covering all sources with climate change to reach Excellent

Previous Version 6 allowed Excellent without any flood credits if scoring well in energy, materials, water, etc. Version 7 removes this flexibility—flood risk competence is non-negotiable for Excellent.

For Outstanding Rating:

Minimum 2 flood risk credits required

This effectively restricts Outstanding to Flood Zone 1 sites only. Sites in Zones 2 or 3 achieve maximum 1 credit (with exceptional resilience), insufficient for Outstanding.

Outstanding rating under Version 7 therefore requires:

• Site in Flood Zone 1 confirmed through FRA

• Comprehensive all-sources assessment with climate change

• Low flood risk maintained through building life (60+ years)

• Surface water flood risk adequately managed

• Groundwater flooding not significant issue

Strategic Implications:

Site Selection Impact:

Flood zone classification now determines maximum achievable BREEAM rating before any design work occurs. A site in Zone 2, regardless of exceptional design quality in all other aspects, cannot exceed Excellent rating. A site in Zone 3b likely cannot exceed Very Good.

This fundamentally changes site acquisition decisions. Developers targeting Outstanding must screen sites for flood zone at initial site selection, before purchase. Buying a Zone 2 site and hoping to achieve Outstanding through exceptional design is no longer viable.

Development Viability:

For sites in Zones 2 or 3, the cost of achieving Excellent (1 credit minimum) increases substantially. Resilience measures—600mm floor level raising, or comprehensive BS 8533 strategies—typically add 3-8% to construction costs depending on site characteristics and building type.

Projects with tight viability margins must factor these flood resilience costs at feasibility stage. The option of ignoring flood risk and compensating elsewhere (viable under Version 6) no longer exists for Excellent-targeted schemes.

Planning Policy Alignment:

Version 7 minimum standards align BREEAM with NPPF requirements more strictly. NPPF already requires similar flood risk demonstrations, but planning often focused on compliance rather than resilience. BREEAM now enforces higher standards, making planning compliance alone insufficient for Excellent/Outstanding ratings.

Climate Change Allowance Changes Version 7

Version 7's shift from +40% to +45% peak flows as default standard reflects updated Environment Agency guidance published 2022-2024.

Updated Allowance Framework:

EA guidance provides climate change allowances varying by:

• River basin district (different catchments have different allowances)

• Vulnerability classification (more vulnerable development = higher allowances)

• Development lifetime (longer life = more climate change impact)

• Flood risk management approach (allowances vary by how resilience achieved)

Version 7 Default Assumptions:

For residential and commercial buildings (60-year life):

England most catchments: +45% peak flows (higher central estimate 2080s)Upland catchments (Northumbria, Cumbria): +50% peak flowsUrban catchments with rapid response: +50% peak flowsCoastal areas: +15mm/year sea level rise (approximately 1m by 2085)

Peak rainfall intensity (for surface water assessment): +40% across most of England

For critical infrastructure (120-year life):

Higher end estimates required: +70% peak flows for most catchmentsCoastal: +20mm/year sea level rise (2.4m by 2145)Peak rainfall: +50% intensity increase

Scotland and Wales:

Climate change factors vary by region, following SEPA (Scotland) and NRW (Wales) guidance.

Scotland: +30% to +50% peak flows depending on catchment characteristicsWales: +40% to +60% peak flows with regional variationBoth: +15mm/year sea level rise (revised 2024)

Application Methodology:

Climate change allowances apply to post-development scenarios, not pre-development baselines (covered in separate surface water credits).

For flood level calculations:

1. Establish baseline 1-in-100 year flood level from EA data or hydraulic modelling

2. Apply +45% to peak flow (most England catchments)

3. Model resulting flood level considering channel capacity, overtopping, and flow routes

4. Use this level + 600mm for freeboard calculations

For surface water drainage:

1. Establish baseline 1-in-100 year rainfall depth from FEH (Flood Estimation Handbook) or local data

2. Apply +40% to rainfall intensity

3. Model resulting flows considering catchment characteristics

4. Size attenuation to accommodate increased flows without flooding

Version 7 Enhancement - Cumulative Climate Impacts:

Not just applying percentage increases—must consider:

• Seasonal patterns changing (winter storms intensifying, summer rainfall reducing)

• Multiple events in short succession (less drying time between floods)

• Combined impacts (fluvial + surface water + groundwater simultaneously)

• Changing land use in catchment affecting run-off

This requires more sophisticated modelling than simple percentage increases to historic events.

Justification for Lower Allowances:

Projects may justify using central (+35%) rather than higher central (+45%) estimates only where:

• Building life demonstrably shorter than 60 years (temporary structures, short-lease developments)

• Development vulnerability lower (non-residential, low-value, quick-to-evacuate)

• Exceptional economic circumstances where higher allowances prevent redevelopment delivering wider regeneration benefits

Requires written justification accepted by BREEAM assessor. Simply stating "planning approved with +35%" isn't sufficient—must demonstrate why lower allowance appropriate.

Upper End Allowances (+70%):

Required for:

• Critical infrastructure (hospitals, emergency services, utilities)

• Developments with design life >100 years

• Highly vulnerable development (care homes, schools)

• Developments in areas with significant flood risk management challenges

Version 7 guidance recommends upper end allowances even for standard developments in very high risk areas (Zone 3, history of severe flooding).

Surface Water Flood Risk Assessment Requirements

Version 7 significantly enhances surface water flooding requirements, recognising this as England's most common flood type.

Updated Surface Water Maps (2024):

EA published updated surface water flood maps in 2024 incorporating:

• Higher resolution LiDAR data (50cm rather than 2m)

• Updated rainfall intensity data reflecting recent climate trends

• Improved urban drainage modelling

• Better representation of surface water flow paths

The updated maps show significantly more properties at risk than 2013 mapping. Many sites showing low surface water risk previously now show medium/high risk.

Mandatory Assessment Requirements:

Version 7 FRAs must include:

Surface water flood extent review:

• 1-in-30 year event (3.3% annual probability) - regular occurrence

• 1-in-100 year event (1% annual probability) - design standard

• 1-in-1000 year event (0.1% annual probability) - extreme event

Flow path analysis:

• Identify routes surface water would take across site during events

• Consider where water enters site (upslope areas, road drainage)

• Assess whether flow paths cross buildings, access routes, or services

• Determine whether site acts as flow pathway affecting downstream properties

Depth and velocity assessment:

• Maximum flood depths expected across site

• Flow velocities (high velocity = more damaging)

• Duration of flooding (brief surface ponding vs sustained inundation)

• Hazard rating combining depth and velocity

Integration with site drainage:

• How site drainage interacts with surface water flooding

• Whether site drainage would be overwhelmed during surface water flood event

• Exceedance routes for flows exceeding drainage capacity

• Whether surface water floods would surcharge site drainage causing internal flooding

Mitigation measures where necessary:

• Site levels and gradients directing water away from buildings

• Thresholds raised above anticipated surface water flood levels

• Permeable surfacing or swales intercepting and managing surface water

• Emergency flow routes through site preventing uncontrolled flooding

Evidence Requirements:

Surface water assessment must include:

• Screenshots from EA surface water flood maps showing site for all three return periods

• Topographic survey overlaid with predicted flood extents

• Flow path analysis with directional arrows showing water movement

• Flood depth analysis at critical locations (building thresholds, access routes)

• Mitigation specification where surface water risk identified

Common Issues:

Sites in fluvial Flood Zone 1 frequently have medium/high surface water flood risk from:

• Locations in valley bottoms where surface water accumulates

• Urban areas with limited drainage capacity during intense rainfall

• Sites downslope from large paved areas generating rapid run-off

• Former river channels or drainage routes (even if not current floodplain)

These require mitigation even though fluvial risk is low. Failing to address surface water risk can reduce flood credits even on Zone 1 sites if surface water flooding affects >25% of site area.

Groundwater Flooding Assessment Requirements

Version 7 introduces explicit groundwater flooding assessment requirements, addressing a source frequently overlooked in previous versions.

Groundwater Flooding Mechanisms:

Groundwater flooding occurs through:

• Rising water tables during prolonged wet periods (weeks/months of rainfall)

• Groundwater emerging at surface through springs or seepages

• Groundwater entering basements or below-ground structures

• Groundwater affecting foundations and ground-bearing slabs

Unlike fluvial or surface water flooding (hours/days duration), groundwater flooding typically lasts weeks to months, causing prolonged damage.

Assessment Requirements:

British Geological Survey Susceptibility Maps:

Review BGS groundwater flood susceptibility mapping showing:

• Areas with potential for groundwater flooding to occur

• Clearwater areas (groundwater flooding potential)

• Superficial deposits areas (groundwater near surface)

• Bedrock aquifer areas (deep groundwater systems)

• Artificially modified ground (made ground, quarries, mines)

Maps classify susceptibility as limited, low, moderate, high, or very high. Sites with moderate or higher susceptibility require detailed assessment.

Local Authority Records:

Review local authority records for:

• Historical groundwater flooding incidents

• Locations of springs or seepages

• Areas known to experience high groundwater

• Developments requiring groundwater management

Many local authorities maintain separate groundwater flooding databases beyond standard flood maps.

Site Investigation:

Sites with moderate/high susceptibility require site investigation confirming:

• Depth to groundwater under typical and elevated conditions

• Soil type and permeability characteristics

• Presence of low-permeability layers affecting groundwater movement

• Evidence of previous groundwater flooding (staining, vegetation patterns)

Trial pits or boreholes with groundwater monitoring provide direct evidence of groundwater levels and seasonal variation.

Mitigation Measures:

Where groundwater flooding risk identified:

For buildings with basements:

• Tanking or waterproofing to appropriate BS 8102 standard

• Groundwater management systems (pumped drainage)

• Floor slabs designed for groundwater uplift pressures

• Monitoring systems detecting groundwater ingress

For buildings without basements:

• Floor slabs elevated above anticipated maximum groundwater level

• Foundation design considering buoyancy and uplift

• Drainage preventing groundwater accumulation beneath slabs

• Services positioned above ground bearing slabs

For site drainage:

• Consider whether groundwater levels affect infiltration drainage viability

• Design assumes groundwater at surface (worst case) for drainage capacity

• Outfalls positioned above maximum groundwater levels

• Emergency overflows preventing system backup

Evidence Requirements:

Groundwater assessment must include:

• BGS susceptibility maps showing site location

• Local authority groundwater flooding records

• Site investigation results (if moderate/high susceptibility)

• Groundwater level monitoring data (if basements or deep foundations proposed)

• Mitigation specifications addressing identified risks

Exemptions:

Sites in urban areas with deep made ground overlying low permeability deposits (e.g., Thames Valley London Clay) typically have limited groundwater flooding susceptibility and may satisfy assessors with desktop review rather than detailed investigation.

Conversely, sites in chalk, limestone, or gravel areas require detailed assessment even if fluvial/surface water risk is low.

How to Achieve Version 7 Flood Risk Credits

Achieving Version 7 flood risk credits requires early engagement, competent technical input, and often design changes compared to Version 6 approaches.

Stage 1: Site Selection and Initial Appraisal

Flood Zone Screening:

Before site acquisition, commission preliminary flood risk screening:

• EA Flood Map for Planning review (fluvial and coastal zones)

• Surface water flood maps review (all three return periods)

• BGS groundwater susceptibility maps

• Local authority flooding records

This takes 1-2 days desk study and identifies whether site can achieve target BREEAM rating:

• Zone 1 + low surface water risk: Outstanding achievable (2 credits possible)

• Zone 1 + moderate surface water risk: Outstanding likely achievable with mitigation

• Zone 2: Outstanding not achievable (maximum 1 credit), Excellent achievable with resilience investment

• Zone 3: Outstanding not achievable, Excellent requires substantial resilience investment

• Zone 3b: Excellent likely not achievable unless water-compatible use only

This information should inform land acquisition decisions. Paying premium land prices for Outstanding-target scheme then discovering site is Zone 2 (preventing Outstanding) creates viability problems.

Preliminary Cost Estimation:

Estimate flood resilience costs at feasibility:

Zone 1 sites: £1,000-10,000 for comprehensive FRA (all sources, hydraulic modelling, climate change)

Zone 2 sites targeting Excellent:£10,000-15,000 for FRA + resilience design + implementation:

• 600mm floor raising: ~3-5% construction cost increase

• BS 8533 strategy: ~2-4% construction cost increase

• Access modifications: ~£50,000-200,000 depending on site constraints

Zone 3 sites targeting Excellent:£15,000-30,000+ for comprehensive resilience:

• FRA and detailed hydraulic modelling: £30,000-60,000

• Major floor level raising or BS 8533 measures: 5-8% construction cost increase

• Access infrastructure: £100,000-500,000 for elevated access

• Services protection: £50,000-150,000

These costs should be built into feasibility appraisals, not discovered during technical design stage.

Stage 2: Concept Design (RIBA Stage 2)

Engage Flood Risk Consultant:

Appoint competent flood risk consultant during concept design, not at planning submission. Required qualifications:

• Chartered engineer status (ICE, CIWEM, IStructE)

• Demonstrable flood risk experience (minimum 5 years)

• Familiarity with EA guidance, Version 7 requirements, and local planning policy

• Professional indemnity insurance >£5 million

Consultant should be involved in site layout decisions, building positioning, access strategies, and finished level setting—all decisions affecting flood risk and BREEAM credits.

Topographic Survey:

Commission accurate topographic survey:

• Levels to 10mm vertical accuracy minimum

• Coverage extending beyond site boundary (100m minimum) to show context

• Features survey including drainage outfalls, watercourses, flood defence infrastructure

• Relate survey to OS datum allowing comparison with EA flood data

Poor quality surveys create uncertainty in flood level calculations, potentially requiring conservative assumptions increasing costs.

Preliminary Flood Risk Assessment:

Complete initial FRA during concept design addressing:

All Sources Assessment:

• Fluvial: EA flood modelling data, hydraulic assessment of nearby watercourses

• Surface water: Updated 2024 maps, flow path analysis, depths and hazards

• Groundwater: BGS susceptibility, local authority records, preliminary SI if necessary

• Sewer: Local water company flooding records, sewer capacity in area

• Other: Reservoirs, canals, artificial sources

Climate Change Application:

• +45% peak flows (England most catchments) for 60-year building life

• +40% peak rainfall intensity for surface water

• Assessment through to 2085 (60 years from 2025 completion)

Flood Zone Confirmation:

• EA data confirmed through hydraulic modelling if within 250m of watercourses

• Consideration of climate change through building life

• Confirmation whether flood zone might change during building life

Initial Mitigation Strategy:

• Appropriate approach (floor raising, BS 8533, combination)

• Preliminary finished level recommendations

• Access strategy options

• Services positioning strategy

This initial FRA (£1,000-5,000 typically) provides sufficient detail for planning application and informs design development, avoiding expensive changes later.

Stage 3: Developed Design (RIBA Stage 3)

Detailed Resilience Strategy:

Develop detailed flood resilience approach:

If 600mm Freeboard Route Selected:

Finished Floor Levels:

• All habitable spaces minimum 600mm above design flood level

• Non-habitable spaces (plant rooms, storage) may be lower but with resilience measures

• Thresholds, doorways, and access points meeting 600mm requirement

Access Design:

• Pedestrian routes achieving 600mm freeboard (ramps, raised walkways, earthworks)

• Vehicle access for refuse collection, deliveries, emergency services

• Parking areas evaluated for flooding (may accept temporary flooding if not critical)

• Gradient checks ensuring DDA compliance and refuse vehicle access (<1:12 gradients typically)

Services Protection:

• Electrical systems above flood level + 600mm

• Mechanical plant above flood level (or flood-resistant enclosures)

• Gas meters and pipework elevated

• Drainage with non-return valves

• Communications infrastructure protected

Emergency Planning:

• Safe refuge areas for buildings with vulnerable occupants

• Evacuation routes identified

• Emergency access confirmed with fire/ambulance services

• Building user guide provisions

If BS 8533 Strategy Selected:

Hierarchy Application:

• Critical elements (electrical intake, data centres) positioned above flood level where possible

• Flood resistance measures (doors, seals, barriers) specified for unavoidable below-flood-level elements

• Flood resilience materials (concrete floors, lime mortar, resistant finishes) for areas accepting controlled flooding

• Emergency measures (temporary barriers) only where other approaches insufficient

Material Specifications:

• Floor construction: solid concrete (no suspended timber), DPM to walls minimum 300mm above flood level

• Wall construction: dense blockwork or concrete (not lightweight blocks), render to flood level + 300mm

• Joinery: Specify flood-resistant doors to BS 851-2, flood boards for windows

• Finishes: Ceramic tiles or similar washable finishes to flood level + 300mm, avoid plasterboard or paper-backed materials

• Services: All electrical points above flood level + 300mm, mechanical services with rapid-drain and clean capability

Recovery Plan:

• Maximum recovery time specified (6 months residential, 3 months commercial)

• Materials selected enabling rapid drying (lime mortar, breathable finishes)

• Contractor arrangements for rapid response after flooding

• Insurance considerations and replacement cost provisions

Detailed Hydraulic Modelling:

If near watercourses (within 250m), detailed hydraulic modelling required:

• 2D hydraulic model of watercourse and floodplain

• Incorporating site topography and proposed development

• Climate change scenarios (+45% peak flows minimum)

• Model outputs showing flood extents, depths, velocities, and hazards

• Sensitivity testing considering different flood mechanisms (fluvial, surface water, combined)

Modelling typically costs £5,000-40,000 depending on complexity, but provides defensible evidence of flood levels and demonstrates appropriate design.

Stage 4: Technical Design (RIBA Stage 4)

Final Evidence Package:

Compile comprehensive evidence for BREEAM assessor:

Flood Risk Assessment:

• Complete FRA document addressing all sources with climate change through building life

• Hydraulic modelling outputs showing design flood levels

• Surface water flow analysis with depths and velocities

• Groundwater assessment with mitigation measures

• All sources considered and risks quantified

Resilience Strategy:

• Either 600mm freeboard drawings showing levels throughout site

• Or BS 8533 strategy document with hierarchy approach, material specifications, and recovery plan

• Confirmation from competent professional certifying strategy adequacy

Site Layout Drawings:

• Finished floor levels annotated

• Access routes with levels and gradients

• Services locations and flood protection measures

• Emergency access and refuge areas

Material Specifications:

• Flood-resistant materials specified with manufacturer certifications

• Installation details for flood barriers, seals, and protection measures

• Maintenance requirements for all flood resilience measures

Climate Change Justification:

• Allowances applied with reference to EA guidance

• Justification for allowances selected (higher central, upper end, etc.)

• Consideration of building lifetime and vulnerability

Competent Professional Certification:

• CV and qualifications of lead flood risk consultant

• Professional indemnity insurance certificate

• Statement confirming compliance with Version 7 requirements

This evidence package typically 50-150 pages depending on project complexity and site constraints.

Stage 5: Construction and Post-Construction

Construction Phase Verification:

Flood resilience measures require verification during construction:

As-built levels:

• Survey confirms finished floor levels achieved as designed

• Thresholds and access routes meeting specifications

• No unauthorized level changes reducing flood protection

Materials Installation:

• Flood-resistant materials installed per specifications

• Seals, barriers, and protection measures correctly fitted

• Drainage and non-return valves functioning correctly

Services Protection:

• Electrical systems positioned as designed above flood levels

• Mechanical plant protected or elevated

• Emergency systems tested

Final Evidence:

• As-built drawings confirming design intent achieved

• Photographs of critical flood protection measures

• Commissioning records for mechanical systems

• Building user guide including flood response procedures

Post-Construction Assessment:

BREEAM assessor reviews:

• As-built evidence demonstrating compliance

• Any variations from design and their flood risk implications

• Confirmation competent professional certifies completion meets requirements

Non-compliance discovered at post-construction stage can result in credits withheld, even if design-stage assessment awarded credits provisionally.

Common Challenges with Version 7 Flood Credits

Challenge 1: Zone 2 Sites Targeting Outstanding

Version 7's 2-credit requirement for Outstanding effectively excludes Zone 2 sites. Maximum achievable is 1 credit (with exceptional resilience), insufficient for Outstanding.

Options:

Option A - Accept Excellent as Target:

Most pragmatic approach for Zone 2 sites. Excellent still represents exceptional performance and achieves market recognition. Cost differential between Excellent and Outstanding often doesn't justify pursuing Outstanding on constrained sites.

Option B - Detailed Assessment Potentially Reclassifying Site:

Very occasionally, sites shown as Zone 2 on EA maps prove to be Zone 1 through detailed hydraulic modelling. This occurs where:

• EA modelling is coarse resolution and site-specific detail shows lower flood levels

• Local flood defence schemes provide protection not reflected in EA mapping

• Historical flood events inform EA mapping but weren't actually representative of site conditions

Requires significant hydraulic modelling investment (£30,000-60,000) with uncertain outcome. Only pursue if strong evidence suggests reclassification is genuinely achievable.

Option C - Abandon Outstanding Target:

Sometimes the honest answer is that site constraints prevent Outstanding. Pursuing unachievable target wastes design effort and delays decision-making. Early acknowledgement allows realistic target setting.

Challenge 2: Access Route Freeboard Requirements

Version 7's requirement for 600mm freeboard on access routes, not just building thresholds, creates significant challenges for constrained urban sites.

The Problem:

A building can be elevated 600mm relatively easily (stepped access, platform construction, basement/podium design). Elevating entire access routes creates gradient issues:

• 1:12 maximum gradient for DDA compliance (5m length gains 400mm height, insufficient for 600mm requirement)

• 1:15 preferred for pushchair/wheelchair users

• Refuse vehicles require <1:12 gradients (steeper grades prevent truck access)

• Ambulances/fire tenders need <1:10 gradients typically

Achieving 600mm elevation from site boundary to building entrance might require:

• 600mm ÷ 1:12 gradient = 7.2m length minimum

• For corner-plot sites with multiple boundaries: 10-15m ramp lengths from each boundary

• Can consume 30-40% of site area on small urban plots

Solutions:

Solution A - Strategic Site Earthworks:

If site has space, regrade entire site rather than individual ramps. Create raised platform for development, with perimeter retaining walls managing level change. This:

• Provides 600mm elevation across entire site

• Avoids excessive ramp lengths

• Works better for larger sites (>0.5 hectares)

• Adds £200,000-500,000 for earthworks and retaining walls

Solution B - BS 8533 Alternative:

Where freeboard route impossible, BS 8533 strategy allows designed flooding with resistance measures. Access routes may flood temporarily if:

• Flooding predictable with sufficient warning (not flash flooding)

• Alternative emergency access routes available

• Buildings themselves protected through resistance/resilience

• Recovery plan addresses temporary access loss

More complex to justify but viable for constrained sites.

Solution C - Split-Level Development:

Design buildings with main entrance at elevated level, secondary access (servicing, parking) at lower level accepting temporary flooding. Requires:

• Careful planning of which functions can tolerate brief access disruption

• Emergency access maintained at elevated level

• Services and critical functions at elevated level

Challenge 3: Surface Water Flood Risk on Zone 1 Sites

Many Zone 1 sites have moderate/high surface water flood risk. Version 7 requires addressing this even though fluvial risk is low.

Assessment:

If surface water flooding affects >25% of site area at 1-in-100 year + 40% climate change:

• Site may reduce from 2 credits to 1 credit despite being fluvial Zone 1

• Mitigation measures required demonstrating surface water managed adequately

• Evidence must show buildings, access, services not vulnerable to surface water flooding

Mitigation Options:

Option A - Site Grading:

Grade site directing surface water away from buildings towards controlled discharge points. Requires:

• Careful coordination with building floor levels

• Suitable outfall locations available

• May conflict with accessibility requirements (sites sloping >1:20)

Option B - Permeable Surfacing:

Extensive permeable paving, rain gardens, or swales capturing surface water before it accumulates. Requires:

• Suitable ground conditions for infiltration

• Sufficient area for SuDS features (20-30% of paved areas)

• Maintenance arrangements

Option C - Raised Thresholds:

Elevate building thresholds above predicted surface water flood depths (typically 100-200mm for surface water, less than 600mm for fluvial). Simpler than full freeboard approach but addresses surface water risk.

Option D - Sump and Pump:

Low-lying areas accepting surface water temporarily, with pumped drainage removing it. Requires:

• Emergency power for pumps

• Capacity for extreme events

• Maintenance procedures

Most schemes use combinations—grading plus permeable surfacing plus raised thresholds—addressing surface water risk through multiple measures rather than relying on single approach.

Challenge 4: Groundwater Flooding in Chalk/Limestone Areas

Sites in chalk or limestone geology face groundwater flooding risk even if fluvial Zone 1 and low surface water risk.

The Problem:

Chalk/limestone aquifers:

• Respond to prolonged wet periods with rising groundwater (weeks/months to rise, months to recede)

• Can cause groundwater to emerge at surface even in elevated areas

• Affect basements severely (hydrostatic uplift, water ingress)

• Impair infiltration drainage (assumes groundwater well below infiltration features)

Assessment Requirements:

Sites in areas with "moderate" or higher BGS groundwater susceptibility require:

• Trial pit or borehole investigation confirming groundwater depth

• Groundwater monitoring over minimum 6 months (ideally 12 months including winter)

• Consideration of maximum groundwater levels in extreme wet periods (use local authority records, not just monitoring period)

Design Implications:

For basement developments:

• BS 8102 Grade 3 waterproofing minimum (tanking + cavity drain)

• Floor slab design for hydrostatic uplift pressures (assume groundwater to surface)

• Sump and pump systems with emergency power

• May render basements unviable economically

For infiltration drainage:

• Infiltration SuDS require minimum 1m clearance between infiltration level and maximum groundwater

• On high groundwater sites, infiltration may be impossible

• Alternative drainage (attenuation with discharge) required

• Affects SuDS hierarchy compliance and surface water credits

Mitigation:

Where groundwater flooding identified:

• Avoid basements if possible (above-ground construction only)

• Floor slabs elevated minimum 300mm above maximum groundwater level

• Foundation design considering buoyancy (soil weight must exceed buoyancy forces)

• Drainage designed assuming groundwater at surface (worst case)

Chalk/limestone sites targeting Outstanding should investigate groundwater thoroughly during feasibility—discovering high groundwater during technical design can render Outstanding unachievable through inability to manage surface water sustainably.

Version 7 Flood Risk FAQ

Our site is Flood Zone 1 on EA maps but surface water maps show medium risk across 40% of site. Can we still achieve 2 credits for Outstanding?

Possibly, but requires demonstrating surface water risk is adequately mitigated. Version 7 assessors evaluate whether surface water flooding would significantly impact the development. If mitigation measures (raised thresholds, site grading, permeable surfacing) demonstrate buildings, access, and services are protected from surface water flooding, 2 credits may be achievable.

However, if surface water flooding would cause significant disruption (flooding buildings, severing access for >12 hours, flooding services), assessors may reduce to 1 credit despite fluvial Zone 1 status. Early engagement with flood risk consultant and BREEAM assessor recommended for these scenarios.

We achieved Excellent under Version 6 on a Zone 2 site without flood credits. Can we achieve Excellent under Version 7?

Yes, but you'll need to gain the minimum 1 flood risk credit now required. This means implementing either 600mm freeboard or BS 8533 resilience strategy—requirements that weren't necessary under Version 6 for Excellent.

Budget for additional flood resilience costs (typically £50,000-150,000 including FRA and design/construction of resilience measures). The good news is that Version 6 required 70% for Excellent, whilst Version 7 requires only 55%, so the overall points total needed is lower even though flood credits become mandatory.

How do we justify +45% climate change allowances to planners who approved our scheme with +35%?

BREEAM Version 7 operates independently from planning requirements. Planning approval with +35% allowances satisfies planning policy, but BREEAM requires +45% for certification.

In your design, you can:

• Meet planning requirements with +35% (satisfying planning conditions)

• Design for +45% (satisfying BREEAM requirements)

Often these align—design for +45%, confirm this exceeds +35% planning requirement, both are satisfied. Only problematic if planning specifically limits development in ways preventing +45% implementation (rare).

If conflict genuinely exists, discuss with BREEAM assessor whether planning requirements can be accepted as equivalent demonstration of appropriate climate change consideration.

Our building has 60-year design life for structure but commercial leases are 15 years. Do we assess for 60-year climate change or 15-year?

Version 7 clarifies this: assess for building physical life (structure), not operational lease lengths. Commercial buildings assessed for 60-year minimum regardless of lease structures. This reflects that buildings often outlive initial occupancies—environmental impacts persist beyond first lease period.

Only exception is genuinely temporary structures with designed removal/demolition within shorter timeframe (temporary exhibitions, construction site facilities, etc.). Standard commercial buildings use 60-year assessment period.

Can we achieve 2 credits if we're Zone 1 but within 500m of Zone 2/3 areas?

Yes. Flood zone classification applies to your site specifically, not surrounding areas. If your site's FRA confirms Zone 1 (with comprehensive all-sources assessment and climate change through building life), you can achieve 2 credits even if immediately adjacent to higher-risk areas.

However, ensure your FRA considers:

• Whether flood flows from adjacent Zone 2/3 areas could affect your site (flow routes, elevated water tables, drainage interactions)

• Residual risks from nearby flood sources

• Cumulative impacts if surrounding areas flood while your site experiences intense rainfall

A site can be Zone 1 whilst having increased residual risks from proximity to flood sources—these need acknowledging and mitigating even if not preventing 2 credit achievement.

Get Expert Version 7 Flood Risk Support

Version 7's enhanced flood risk requirements create substantially more complexity than previous versions, with stricter standards, mandatory minimums for higher ratings, and greater emphasis on genuine resilience over compliance exercises.

Our CIWEM-qualified flood risk consultants have supported multiple Version 7 projects, understanding both the technical requirements and practical implementation challenges. We provide comprehensive flood risk services aligned with Version 7 standards:

Feasibility Stage Services:

• Flood zone screening before land acquisition

• Preliminary flood risk assessment

• BREEAM achievability appraisal (can Outstanding be reached on this site?)

• Budget cost estimation for flood resilience measures

Design Stage Services:

• Site-specific FRA addressing all sources with Version 7 climate change allowances

• Detailed hydraulic modelling where required

• Surface water flood risk assessment using 2024 updated maps

• Groundwater flooding assessment with site investigation coordination

• Resilience strategy development (600mm freeboard or BS 8533 approach)

• Access and services design coordination

BREEAM Certification Support:

• Evidence package preparation for BREEAM assessors

• Technical queries response during assessment

• Post-construction verification

• Version 7 compliance certification

Version 6 to Version 7 Transition:

• Gap analysis for projects considering Version 7 upgrade

• Minimum standards compliance verification

• Additional work scope and cost implications

• Strategic recommendation on version choice

Based in London and operating throughout Kent, Essex and Scotland, we deliver rapid turnaround for developments requiring Version 7 BREEAM flood risk assessment. Our team combines hydrological expertise with practical construction knowledge, ensuring flood resilience strategies work in real-world delivery whilst achieving BREEAM certification requirements.

Professional indemnity insurance exceeds £1 million, and we maintain robust quality assurance procedures for all technical work. We're fully familiar with Version 7 requirements having worked extensively with the technical manual, BRE guidance, and multiple Version 7 project applications.

Contact us to discuss your Version 7 flood risk requirements