Fact 32. Flood Risk - what are the issues?
Flood risk can lower property value, complicate insurance and mortgage approval, and requires thorough investigation in UK conveyancing transactions.
Flooding has become one of the most significant natural risks for property owners in the UK. With rising sea levels, increasingly heavy rainfall events, and climate change driving new patterns of weather, the need to properly understand and address flood risk during the conveyancing process has never been greater. For buyers, sellers, conveyancers, mortgage lenders and insurers, knowledge of a property’s flood exposure is essential for both immediate decision-making and long-term protection.
Introduction to Flood Risk in Property Transactions
Almost one in four homes in England are currently at risk from flooding, whether from rivers, the sea, or surface water run-off. According to Environment Agency research in December 2024, this equates to about 6.3 million properties, and that figure is set to rise. By 2050, some projections suggest as many as 8 million UK homes could be exposed to significant flood risk. This growing threat has major implications for home buyers, sellers, mortgage lending, and insurance across the nation.
Understanding Flood Risk: Types and Causes
Flood risk in the UK predominantly falls into four categories:
River (fluvial) flooding: Water from rivers and streams overflowing their banks, often following heavy or prolonged rain.
Coastal flooding: Caused by high tides, sea surges, or storm-driven waves breaching defences along the coastline.
Surface water (pluvial) flooding: Heavy rainfall overwhelms drainage systems and cannot soak into ground fast enough, causing urban or rural flash flooding.
Groundwater flooding: Prolonged rainfall or rising water tables cause water to emerge at the surface, often impacting basements or properties on low-lying land.
Factors increasing a property’s susceptibility include its location (proximity to rivers, coasts, low-lying landscapes), local topography, and the effectiveness (or absence) of flood defences in the surrounding area. Not all at-risk properties are equally exposed—a flood map may not distinguish between a house at the top of a hill and another at street level just a few metres away.
Flood Risk and the Conveyancing Process
For solicitors and licensed conveyancers, due diligence on flood risk is now a standard part of the process. Comprehensive investigations can involve:
Environmental searches: These often flag up whether a property may be at risk based on Environment Agency or similar data.
Dedicated flood risk reports: Specialist reports provide detailed assessments using local river/coastal/borehole data, and may include:
Historical flood records or events
Predicted water levels and depths
Details on flood defences, their condition, and proximity
Soil and groundwater data
These reports can cost between £20-£25 plus VAT for a standard search, with upgrades for larger plots. The information must be current—usually no older than six months at completion—according to lender requirements.
Key Issues Raised by Flood Risk in Conveyancing
For buyers and sellers alike, flood risk presents several practical and legal challenges:
Property Value and Saleability
Evidence of previous flooding or a high risk rating can significantly reduce a property’s value and limit its marketability. Purchasers may be deterred by concerns about future sale prospects, as well as the practical realities of living in a flood-prone home.Obtaining Insurance
Insurance availability and cost are profoundly affected by flood risk. Although home insurance in the UK commonly includes flood cover as standard, those in high-risk zones have historically faced high excesses, expensive premiums, or outright refusals.
To address this, the government and insurers launched the Flood Re scheme in 2016. Under this system, insurers can transfer (“cede”) high flood-risk policies to a central pool, allowing the customer to obtain affordable flood insurance. However, this only assists:
Homes built before 1 January 2009 (newer builds are ineligible)
Owner-occupied homes (not commercial, buy-to-let, or large blocks of flats)
Properties built after 2009 or various categories (such as commercial units) remain excluded from the scheme, requiring alternative or often more costly arrangements.
Getting a Mortgage
Exposure to flood risk and the outcome of flood searches directly affects mortgage lending. Major lenders now routinely use mapping technology to flag up at-risk properties and may outright refuse a mortgage for those at high risk. In April 2024, for example, one of the UK’s largest lenders confirmed its policy to decline home loans on properties they judged as unacceptably exposed to flooding—even if the buyer was happy to accept the insurance implications.Planning and Development Considerations
Developers are legally required to undertake a detailed Flood Risk Assessment (FRA) before building on at-risk land, as per the National Planning Policy Framework (NPPF). This must assess:
Current and future flood risk (including the impacts of climate change)
How development may alter the risk profile in the wider community
Whether proposed flood defences or mitigation measures will remain effective for the intended lifetime of the buildings
Failure to follow best practice can leave new homes without adequate protection, and these post-2009 properties won’t be backed by Flood Re.
Practical Steps for Buyers and Sellers
Given the complexity and potential consequences, thorough investigation and transparent communication are essential for any property transaction in a flood risk area. For buyers, due diligence should involve:
Reviewing the results of environmental and dedicated flood risk searches
Asking the seller for information about historic flooding or mitigation measures in place (such as raised electrical sockets, non-return valves, air brick covers, and water-resistant plaster)
Noting any local flood defences or warning systems
Checking with multiple insurers about the availability and affordability of cover
Confirming that a mortgage offer is valid and will not be withdrawn due to search results
For sellers, preemptively ordering and sharing flood risk or environmental searches can help avoid shocks or delays later in the process and demonstrate honesty and preparedness to potential buyers.
The Role of Flood Risk Reports
Flood risk reports form a vital part of modern conveyancing, typically including the following:
Assessment from expert environmental consultants
Insurability statement—highlighting potential issues with obtaining cover
Data on rivers, coasts, surface water, groundwater flooding, and reservoirs
Recommendations for next steps where risks are identified
Suggestions for resilience or mitigation actions
Searches are not automatically compulsory but may become so if triggered by a lender, buyer request, or if environmental searches suggest significant risk. They are generally effective for six months as per UK finance requirements.
Insurance: The Ongoing Challenge
Flood insurance remains a concern, even with the intervention of schemes like Flood Re. For high-risk properties outside Flood Re’s eligibility, insurance premiums can be 25% higher than average, with excesses for flood claims sometimes reaching £5,000. It’s also a condition of most mortgages that buildings insurance (including flood cover) must be in place by completion.
Post-2039, uncertainty surrounds the future of Flood Re, which is currently set to end. Without renewed government intervention, the insurance market may again become restrictive and expensive for those in high-risk areas.
Climate Change: A Growing Danger
Climate change is already shifting rainfall patterns, bringing heavier downpours and longer wet spells to the UK. This not only increases river and surface flooding but also elevates groundwater levels and erodes the reliability of flood defences. More severe weather means even areas not previously affected may face new or increased risk—making comprehensive investigative searches ever more important.
Practical Examples and Key Facts
Eight percent of all new homes built during the past decade were located in flood zones, a figure that equates to around 110,000 properties.
Over 99% of householders in high-risk areas were able to find insurers thanks to Flood Re, compared to fewer than 10% before its introduction.
Environmental searches and flood risk reports range in cost but typically start from £20-£25 for a basic report.
The National Planning Policy Framework demands that all new developments at risk must be reviewed for both current risk and climate change vulnerability.
Current Defences and Future Outlook
Many UK cities benefit from large-scale flood defences, such as the Thames Barrier, extensive levees, and improved drainage systems. Despite these, local failures still occur, and defences do not always guarantee protection—defence maps are not fool-proof, and properties can remain vulnerable. Ongoing maintenance and future investment in both community-level and property-level resistance measures are crucial.
Practical Tips for Minimising Flood Risk Impact
Consider property-level resilience improvements, such as installing flood doors, barriers, or pumps.
Ensure clear drains, gutters, and local ditches.
Register with the Environment Agency’s free flood alert service for warnings in affected areas.
Store valuables on upper floors or raised fixtures where feasible.
Key Takeaway Points
Always conduct thorough environmental and flood risk searches as early as possible in the conveyancing process.
Carefully assess the insurability and potential insurance costs of the property.
Check lender requirements and confirm that mortgage approval is not conditional on a favourable flood risk outcome.
For sellers, be up front and organised with documentation about the property’s flood risk and any measures taken to reduce it.
Understand that climate change and evolving national policy may alter risk patterns over time—today’s “safe” zone might face future threat.
Seek specialist legal or insurance advice if in doubt, especially for unusual or high-risk situations.