England has built 109,000 homes in high-risk flood zones over the past decade. Analysis suggests over 100,000 more could be built in the next five years to meet the government’s 1.5 million housing target, though the government disputes these projections. The problem: these homes will become uninsurable when the Flood Re scheme expires in 2039.
The Scale of the Problem
One in thirteen new homes built since 2013 sits in Flood Zone 3—areas with a 1 in 100 annual probability of river flooding or 1 in 200 for sea flooding. Three in five residents believe their home faces flood risk. One in eight report their home has already flooded within five years of construction.
The East of England, Yorkshire and the Humber, and the North West face the highest risk, with flood probabilities between 10% and 12%. Hull, Boston, and areas along the Thames estuary continue to approve developments despite repeated flooding.
Why Development Continues in Danger Zones
A UK Parliament report concluded the planning system “is not keeping pace with the modern realities of flooding but is instead building risk into the landscape.”
Over half of Local Planning Authorities rarely or never inspect new developments to verify compliance with flood risk conditions. The Environment Agency, a statutory consultee on flood risk, lacks enforcement power to block developments. Councils face pressure to meet housing targets, often overriding flood concerns.
Developers argue that modern flood defenses and building techniques mitigate risk. But 7% of England’s flood defenses are in poor condition, with 1% classified as very poor. The Environment Agency estimates 203,000 properties face increased risk due to deteriorating defenses.
The Insurance Crisis Looming
Flood Re, launched in 2016, currently caps flood insurance premiums for at-risk properties through a levy on all UK home insurance policies. Without it, flood insurance for high-risk homes becomes unaffordable or unavailable.
The scheme expires in 2039 and excludes homes built after 2009. The 109,000 homes built in flood zones since 2013 already fall outside this protection. When Flood Re ends, banks will refuse mortgages on uninsurable properties, collapsing values in affected areas.
The Financial Impact
Homes at flood risk already sell for 8% less. The highest-risk properties drop up to 32%. The Bank of England warns the most vulnerable 1% could lose 20% of their value under pessimistic climate scenarios.
Average flood damage costs £33,000 per claim. Storm Babet in October 2023 produced single claims approaching £450,000. Beyond property damage, flooding causes long-term health impacts, business disruption, and community displacement.
Climate change accelerates the timeline. One in six properties in England will face flood risk by 2050, with millions more at risk from both river and surface water flooding in coming decades.
Permitted Development Bypasses Flood Safety
Thousands of affordable homes have been lost through office-to-residential conversions under permitted development rights. These conversions bypass normal planning scrutiny, including flood risk assessments.
Councils can’t enforce affordable housing requirements, flood resilience standards, or infrastructure contributions. The result: smaller, poorly ventilated homes in unsuitable locations, including flood zones, with no requirement for flood-resistant construction.
Solutions Exist But Remain Voluntary
British Standard BS 85500, updated in 2025, provides detailed guidance for flood-resilient construction:
• Finished floor levels at minimum 600mm above estimated flood levels
• Ground-bearing concrete floors (minimum 150mm) over continuous damp-proof membranes
• Solid wall construction with external insulation
• Closed-cell insulation that resists water penetration
• Water entry strategies for deep flooding—allowing controlled water entry to prevent structural damage while using water-resistant materials that dry quickly
The Netherlands demonstrates what’s possible. Dutch building codes mandate amphibious foundations in flood zones—structures that float on rising water. The UK has the technical knowledge but lacks mandatory enforcement.
Some UK developments have successfully incorporated flood resilience measures, including sustainable drainage systems (SuDS), retention ponds, and elevated construction that have kept properties dry during flooding events.
What Needs to Change
The UK Parliament report recommends:
• Making BS 85500 mandatory for all new builds in flood zones
• Giving the Environment Agency veto power over high-risk developments
• Requiring retrofit flood resilience for existing at-risk properties
• Extending Flood Re beyond 2039 or creating alternative protection
• Ending permitted development rights in flood zones
The government has committed £2.4 billion for flood defenses over 2024-26. However, experts warn current investment levels fall short of what’s needed to prevent worsening risk while development continues in vulnerable areas.
We’re creating a two-tier housing market: properties that can be insured and mortgaged, and those that can’t. The 109,000 homes already built in flood zones will bear the consequence. The question is whether we’ll stop before building tens of thousands more.