BH19 1AR - Flood, Heat, Air & Subsidence Risk - Swanage

Dorset, Swanage

BH19 1AR in Swanage has a Very low flood risk - EA NaFRA2 data records no properties in a flood risk zone in this postcode. Heat risk is Lower, with a median (50th percentile) of 23 days above 25°C per year, averaged over the 2021-2040 period under the RCP8.5 high emissions scenario (Met Office UKCP18). Air quality is Low at PM2.5 5.5 μg/m³, above the WHO annual guideline of 5 μg/m³ (Defra UK-AIR). Ground conditions are Medium risk, with Claystone/Mudstone geology; shrink-swell risk is classed as possible (BGS GeoSure).

• Flood: EA NaFRA2: no properties at flood risk in this postcode.
• Heat: Projected 23 days above 25°C per year, 2021-2040 average (Met Office UKCP18, 50th percentile under RCP8.5).
• Air quality: PM2.5 5.5 µg/m³ - above the WHO annual guideline of 5 µg/m³ (Defra UK-AIR).
• Ground: BGS data: Claystone/Mudstone geology. Shrink-swell risk classed as possible (British Geological Survey).
• Green space: 11% of addresses within 200m of green space - near the England median (ONS).

Flood risk at BH19 1AR is rated Very Low, based on Environment Agency NaFRA2 modelling.

Air quality at BH19 1AR is rated Low, based on Defra UK-AIR annual mean PM2.5 data. Fine particulate matter (PM2.5) comes primarily from road traffic, industry, and domestic burning. Long-term exposure above the WHO guideline of 5 µg/m³ is linked to respiratory and cardiovascular health risks. Buyers and renters in higher air quality risk areas may wish to consider whether the property is near busy roads or industrial sources.

BGS GeoSure data classes the underlying soil at BH19 1AR as Claystone/Mudstone, with shrink-swell hazard rated possible (subsidence risk band: Medium). Soil type and shrink-swell behaviour drive subsidence claims following dry summers; recent ABI data shows insurer payouts rose sharply after the 2022 and 2025 hot summers. A structural survey is the reliable way to assess ground risk for a specific property.

This LocalRisk report for BH19 1AR draws on four official UK open data sources: Environment Agency NaFRA2 flood modelling, Met Office UKCP18 climate projections, Defra UK-AIR PM2.5 monitoring, and British Geological Survey GeoSure subsidence mapping. Risk ratings are a screening tool, complementing - not replacing - the searches and surveys ordered as part of a property transaction. Data covers Dorset and is updated as new official datasets are published.

Dorset has a mixed coastal and rural setting with chalk downland, river valleys and low-lying plains and experiences cool, wet winters and warm summers, shaped by maritime influence and varied topography.

Environment Agency flood zone data shows very low flood risk for BH19 1AR in Swanage. EA NaFRA2 data shows no properties at flood risk in this postcode. The band reflects the highest flood risk within the postcode; some properties within this postcode may face little or no direct flood risk. For a specific property, a conveyancing search will confirm the exact flood zone position.

Practical check: With 23 hot days projected (UKCP18 50th percentile, 2021-2040 average under RCP8.5), note which bedrooms face west (hottest in evening) and whether windows allow through-ventilation. With claystone/mudstone geology here, look for signs of ground movement - diagonal cracks above windows, sticking doors, and gaps between walls and extensions. These are postcode-level indicators - conditions vary between individual properties.