London, Essex, and East Yorkshire top the regulator's new exposure map
The Financial Conduct Authority has published its first detailed look at how regulated mortgage lending in England overlaps with flood risk - and the numbers are worth paying attention to. Around 15.5% of mortgage contracts are linked to postcodes with some level of exposure to flooding from rivers, the sea, or surface water.
The data, released on 26 October, is not a stress test. It does not create new rules. The FCA was upfront about that. But it is the regulator turning its climate lens directly onto the mortgage book, and the regional breakdown is granular enough to make any lender or broker with a concentrated book want to check their own exposure.
How the FCA built the map
The FCA took postcode locations from mortgage reporting data and mapped them against Environment Agency flood risk datasets covering three sources: rivers, the sea, and surface water. A postcode gets tagged to a risk band when its centroid - the approximate geographic centre of the postcode - falls inside a flood risk area.
It is a blunt tool by design. The analysis works at postcode level, not property level, and the FCA flagged that limitation repeatedly. But the dataset underneath is deep. Firms have been required to report data on all new regulated mortgage sales since 2005. Since 1 April, 2021, that reporting has also covered internal product transfers and further advances.
The result: roughly 1 in 7 mortgage contracts in England sit in postcodes with some level of flood risk. That exposure is anything but evenly spread.
London and Essex lead on surface water
Surface water flooding - the kind driven by heavy rain overwhelming drainage - is concentrated in the capital and its surroundings. Inner London West leads the table, with 24% of mortgage contracts in flood-exposed postcodes. Inner London East follows at 21%. Essex comes in at 18% overall but carries the highest share of contracts in the "high risk" surface water band at 6.5%.
Merseyside, Cambridgeshire and Peterborough, and Outer London South each came in around 14% to 15%.
Lincolnshire and East Yorkshire top the river and sea table
River and sea flooding draws a completely different map. The FCA's own analysis found this type of exposure "is highest in Lincolnshire and East Yorkshire, where a large portion of postcodes fall within the medium and high-risk categories." The Lincolnshire sub-region has a combined medium-and-high-risk share of 8.3%, while East Yorkshire and Northern Lincolnshire carries the largest total affected share of any region at 38% - driven largely by the Humber estuary and low-lying coastal geography.
The FCA broke the data across 36 sub-regions. The granularity means a lender with a regional book could overlay this against their own portfolio without much trouble.
No clear link between high LTV lending and flood zones
One question the FCA tested: does higher loan-to-value lending cluster in flood-prone postcodes? That pattern would amplify losses if property values dropped after a flood event.
The short answer is no. The regulator found "the results do not show a clear or consistent relationship between higher LTV lending and greater exposure to flood risk."
One wrinkle stood out: mortgages with LTV ratios above 100% showed a notable increase in medium-risk surface water areas. The FCA stopped short of drawing conclusions from that.
Deprivation tells two different stories
The FCA cross-referenced flood exposure against the Index of Multiple Deprivation, England's official measure of socioeconomic disadvantage. The results split sharply by flood type.
For surface water flooding, more deprived communities carry a disproportionate share of the risk. Within each flood risk band, a higher proportion of mortgages are linked to the most deprived postcodes compared to postcodes with no flood risk.
For river and sea flooding, the relationship flips. As risk increases, a larger share of mortgages sit in less deprived areas. The FCA said this "may reflect the attractiveness of some properties located near rivers or along the coast" - a dynamic familiar to anyone who has priced waterfront property.
What it means and what it does not
The publication sits under the FCA's broader climate adaptation and resilience workstream. It "does not introduce new regulatory requirements or supervisory expectations," the regulator said. The analysis is positioned as a tool to help the FCA identify where physical climate risks are most relevant to mortgage lending and consumer outcomes.
The FCA completed parallel analysis for Scotland and Wales but could not apply the methodology consistently because of differences in geography and population density. Northern Ireland was excluded because comparable flood risk data is not available.
For mortgage professionals with English lending books, the signal is straightforward: the regulator now holds a postcode-level view of where flood risk intersects with the mortgage market, and it has chosen to make that picture public. Whether this feeds into future supervisory focus, product design expectations, or Consumer Duty thinking remains to be seen - but the groundwork is on the record.
The FCA cautioned that the analysis does not assess individual properties, firms, or consumer outcomes, and should not be read that way.
